Fix docs for example/example_group alias methods.
Fix docs for example/example_group alias methods.

We were getting YARD doc warnings:

$ bin/yard server --reload

[warn]: @param tag has unknown parameter name: name
    in file `lib/rspec/core/example_group.rb' near line 122
[warn]: @param tag has unknown parameter name: extra_options
    in file `lib/rspec/core/example_group.rb' near line 122
[warn]: @param tag has unknown parameter name: implementation
    in file `lib/rspec/core/example_group.rb' near line 122
[warn]: @param tag has unknown parameter name: name
    in file `lib/rspec/core/example_group.rb' near line 125
[warn]: @param tag has unknown parameter name: extra_options
    in file `lib/rspec/core/example_group.rb' near line 125
[warn]: @param tag has unknown parameter name: implementation
    in file `lib/rspec/core/example_group.rb' near line 125
[warn]: @param tag has unknown parameter name: name
    in file `lib/rspec/core/example_group.rb' near line 134
[warn]: @param tag has unknown parameter name: extra_options
    in file `lib/rspec/core/example_group.rb' near line 134
[warn]: @param tag has unknown parameter name: implementation
    in file `lib/rspec/core/example_group.rb' near line 134
[warn]: @param tag has unknown parameter name: name
    in file `lib/rspec/core/example_group.rb' near line 138
[warn]: @param tag has unknown parameter name: extra_options
    in file `lib/rspec/core/example_group.rb' near line 138
[warn]: @param tag has unknown parameter name: implementation
    in file `lib/rspec/core/example_group.rb' near line 138
[warn]: @param tag has unknown parameter name: name
    in file `lib/rspec/core/example_group.rb' near line 141
[warn]: @param tag has unknown parameter name: extra_options
    in file `lib/rspec/core/example_group.rb' near line 141
[warn]: @param tag has unknown parameter name: implementation
    in file `lib/rspec/core/example_group.rb' near line 141
[warn]: @param tag has unknown parameter name: name
    in file `lib/rspec/core/example_group.rb' near line 144
[warn]: @param tag has unknown parameter name: extra_options
    in file `lib/rspec/core/example_group.rb' near line 144
[warn]: @param tag has unknown parameter name: implementation
    in file `lib/rspec/core/example_group.rb' near line 144
[warn]: @param tag has unknown parameter name: name
    in file `lib/rspec/core/example_group.rb' near line 147
[warn]: @param tag has unknown parameter name: extra_options
    in file `lib/rspec/core/example_group.rb' near line 147
[warn]: @param tag has unknown parameter name: implementation
    in file `lib/rspec/core/example_group.rb' near line 147
[warn]: @param tag has unknown parameter name: name
    in file `lib/rspec/core/example_group.rb' near line 150
[warn]: @param tag has unknown parameter name: extra_options
    in file `lib/rspec/core/example_group.rb' near line 150
[warn]: @param tag has unknown parameter name: implementation
    in file `lib/rspec/core/example_group.rb' near line 150
[warn]: @param tag has unknown parameter name: name
    in file `lib/rspec/core/example_group.rb' near line 153
[warn]: @param tag has unknown parameter name: extra_options
    in file `lib/rspec/core/example_group.rb' near line 153
[warn]: @param tag has unknown parameter name: implementation
    in file `lib/rspec/core/example_group.rb' near line 153
[warn]: @param tag has unknown parameter name: name
    in file `lib/rspec/core/example_group.rb' near line 156
[warn]: @param tag has unknown parameter name: extra_options
    in file `lib/rspec/core/example_group.rb' near line 156
[warn]: @param tag has unknown parameter name: implementation
    in file `lib/rspec/core/example_group.rb' near line 156
[warn]: @param tag has unknown parameter name: name
    in file `lib/rspec/core/example_group.rb' near line 159
[warn]: @param tag has unknown parameter name: extra_options
    in file `lib/rspec/core/example_group.rb' near line 159
[warn]: @param tag has unknown parameter name: implementation
    in file `lib/rspec/core/example_group.rb' near line 159
[warn]: @param tag has unknown parameter name: name
    in file `lib/rspec/core/example_group.rb' near line 162
[warn]: @param tag has unknown parameter name: extra_options
    in file `lib/rspec/core/example_group.rb' near line 162
[warn]: @param tag has unknown parameter name: implementation
    in file `lib/rspec/core/example_group.rb' near line 162
[warn]: @param tag has unknown parameter name: name
    in file `lib/rspec/core/example_group.rb' near line 231
[warn]: @param tag has unknown parameter name: metadata
    in file `lib/rspec/core/example_group.rb' near line 231
[warn]: @param tag has unknown parameter name: name
    in file `lib/rspec/core/example_group.rb' near line 236
[warn]: @param tag has unknown parameter name: metadata
    in file `lib/rspec/core/example_group.rb' near line 236
[warn]: @param tag has unknown parameter name: name
    in file `lib/rspec/core/example_group.rb' near line 241
[warn]: @param tag has unknown parameter name: metadata
    in file `lib/rspec/core/example_group.rb' near line 241
[warn]: @param tag has unknown parameter name: name
    in file `lib/rspec/core/example_group.rb' near line 245
[warn]: @param tag has unknown parameter name: metadata
    in file `lib/rspec/core/example_group.rb' near line 245
[warn]: @param tag has unknown parameter name: name
    in file `lib/rspec/core/example_group.rb' near line 249
[warn]: @param tag has unknown parameter name: metadata
    in file `lib/rspec/core/example_group.rb' near line 249
[warn]: @param tag has unknown parameter name: name
    in file `lib/rspec/core/example_group.rb' near line 253
[warn]: @param tag has unknown parameter name: metadata
    in file `lib/rspec/core/example_group.rb' near line 253
[warn]: @param tag has unknown parameter name: name
    in file `lib/rspec/core/example_group.rb' near line 257
[warn]: @param tag has unknown parameter name: metadata
    in file `lib/rspec/core/example_group.rb' near line 257
h4ck3rm1k3/rspec-core,dg-ratiodata/rspec-core,urbanautomaton/rspec-core,SoldierCoder/rspec-core,azbshiri/rspec-core,arronmabrey/rspec-core,xmik/rspec-core,a-suenami/rspec-core,rspec/rspec-core,rspec/rspec-core,eugeneius/rspec-core,edwardpark/rspec-core,pandabrand/rspec-core,h4ck3rm1k3/rspec-core,urbanautomaton/rspec-core,irfanah/rspec-core,Teino1978-Corp/Teino1978-Corp-rspec-core,Teino1978-Corp/Teino1978-Corp-rspec-core,yaoshipu/rspec-core,iguchi1124/rspec-core,maclover7/rspec-core,avantcredit/rspec-core,pandabrand/rspec-core,dg-ratiodata/rspec-core,leg100/rspec-core,leg100/rspec-core,danascheider/rspec-core,rspec/rspec-core,SoldierCoder/rspec-core,behnaaz/rspec-core,yaoshipu/rspec-core,edwardpark/rspec-core,edwardpark/rspec-core,arronmabrey/rspec-core,irfanah/rspec-core,leg100/rspec-core,behnaaz/rspec-core,xmik/rspec-core,behnaaz/rspec-core,iguchi1124/rspec-core,yaoshipu/rspec-core,iguchi1124/rspec-core,a-suenami/rspec-core,eugeneius/rspec-core,danascheider/rspec-core,azbshiri/rspec-core,xmik/rspec-core,arronmabrey/rspec-core,maclover7/rspec-core,eugeneius/rspec-core,avantcredit/rspec-core,avantcredit/rspec-core,pandabrand/rspec-core,irfanah/rspec-core,maclover7/rspec-core,h4ck3rm1k3/rspec-core,Teino1978-Corp/Teino1978-Corp-rspec-core,azbshiri/rspec-core,urbanautomaton/rspec-core,danascheider/rspec-core,SoldierCoder/rspec-core,a-suenami/rspec-core,dg-ratiodata/rspec-core