fix for/for_class parameter that don't match between doc and code

The documentation describing the apply_base_class_role() method of the
Mouse::Util::MetaRole package, and other similar methods, explains that
it takes "for" parameter.

However, they actually take a parameter with the name "for_class", which
can be confusing to users and needs to be fixed.

And also, other packages may already be calling the
apply_base_class_role() method and using the name “for_class”, so I've
allowed them to do so to maintain compatibility.

Signed-off-by: Jihyeon Gim <[email protected]>

Author: potatogim

Moose-t-failing/050_metaclasses/050_metarole_backcompat.t

@@ -223,8 +223,8 @@ use Mouse::Util::MetaRole;
 
 {
     Mouse::Util::MetaRole::apply_base_class_roles(
-        for_class => 'My::Class',
-        roles     => ['Role::Foo'],
+        for   => 'My::Class',
+        roles => ['Role::Foo'],
     );
 
     ok( My::Class->meta()->does_role('Role::Foo'),

lib/Mouse/Util/MetaRole.pm

@@ -108,7 +108,7 @@ sub _fixup_old_style_args {
 sub apply_base_class_roles {
     my %options = @_;
 
-    my $for = $options{for_class};
+    my $for = $options{for} // $options{for_class};
 
     my $meta = Mouse::Util::class_of($for);