Fix hypothetical Java example
Fix hypothetical Java example

The documentation had an example rule for a hypothetical compile of
a .java file that would compile down to a .class file, but the
example began with:

    rule '.java' => ...

Since the extension after 'rule' is supposed to be the target
extension rather than the source extension, it should begin with:

    rule '.class' => ...

taiganakagawa/rake,pjump/rake,jaustinhughey/rake,zzak/rake,88rabbit/rake,utilum/rake,esasse/rake,ruby/rake,envato/rake,hsbt/rake,bentley/rake,ipmobiletech/rake,codedogfish/rake,envato/rake,hsbt/rake,Vanzct/rake,tmornini/rake,ruby/rake,askl56/rake