Fix RDoc copy-pasta in Chef::Mixin::ParamsValidate#validate
Fix RDoc copy-pasta in Chef::Mixin::ParamsValidate#validate

Signed-off-by: Reuben Garrett <18e40e1401eef67e1ae69efab09afb71f87ffb81@rubydono.net>

The RDoc for `Chef::Mixin::ParamsValidate#validate`
appears to have inadvertently copied the (helpful)
inline pseudocode of the `:is` option to the `:equal_to` option
in commit 28f17b36a9d041be8ed50e20ae06fa5f5ea1fb38.

Obvious fix.
MsysTechnologiesllc/chef,mattray/chef,jaymzh/chef,nvwls/chef,gene1wood/chef,higanworks/chef,gene1wood/chef,jaymzh/chef,MsysTechnologiesllc/chef,higanworks/chef,mwrock/chef,gene1wood/chef,tas50/chef-1,gene1wood/chef,jaymzh/chef,higanworks/chef,nvwls/chef,chef/chef,chef/chef,jaymzh/chef,mattray/chef,tas50/chef-1,chef/chef,MsysTechnologiesllc/chef,chef/chef,MsysTechnologiesllc/chef,mattray/chef,nvwls/chef,higanworks/chef,tas50/chef-1,nvwls/chef,nvwls/chef,higanworks/chef,mattray/chef,mwrock/chef,mwrock/chef,nvwls/chef,mwrock/chef,mattray/chef,tas50/chef-1