[S32/Containers] removed parameter to .keys etc

You could match on indexes/keys using an optional parameter on the .keys,
.values, .pairs, .enums, .kv methods. I discovered this by accident, and
went to check the source of both Rakudo and Niecza. Neither implements this
parameter. It's a very old parameter, but it seems no-one has cared about
it enough to ask for it or implement it. Besides, there are better, more
readable ways to accomplish the same thing:

    %h.values(/^prefix/);                         # instead of this...

    %h.pairs.grep({.key ~~ /^prefix/})».value;    # ...do this
    %h.kv.map({ $^value if $^key ~~ /^prefix/ }); # ...or this
    %h{%h.keys.grep(/^prefix/)};                  # ...or even this

There are plenty of alternative ways to emulate the functionality that
the parameter provided, all of them (in my opinion) more tractable.

S32-setting-library/Containers.pod

@@ -19,8 +19,8 @@ DRAFT: Synopsis 32: Setting Library - Containers.pod
 
     Created: 19 Feb 2009 extracted from S29-functions.pod
 
-    Last Modified: 14 Jan 2011
-    Version: 26
+    Last Modified: 5 Feb 2011
+    Version: 27
 
 The document is a draft.
 
@@ -732,17 +732,14 @@ returns the modified array.
 
 =item values
 
- multi method keys   ( @array: Matcher $indextest? ) is export
- multi method kv     ( @array: Matcher $indextest? ) is export
- multi method pairs  ( @array: Matcher $indextest? ) is export
- multi method enums  ( @array: Matcher $indextest? ) is export
- multi method values ( @array: Matcher $indextest? ) is export
+ multi method keys   ( @array: ) is export
+ multi method kv     ( @array: ) is export
+ multi method pairs  ( @array: ) is export
+ multi method enums  ( @array: ) is export
+ multi method values ( @array: ) is export
 
 Iterates the elements of C<@array>, in order.
 
-If C<$indextest> is provided, only elements whose indices match
-C<$index ~~ $indextest> are iterated.  (To select on values use C<grep>.)
-
 What is returned at each element of the iteration varies with function.
 C<values> returns the value of the associated element; C<kv> returns
 a 2 element list in (index, value) order, C<pairs> a C<Pair(index, value)>.
@@ -787,19 +784,16 @@ which can be processed using junctions.
 
 =item values
 
- multi method keys   ( %hash: Matcher $keytest? ) is export
- multi method kv     ( %hash: Matcher $keytest? ) is export
- multi method pairs  ( %hash: Matcher $keytest? ) is export
- multi method enums  ( %hash: Matcher $keytest? ) is export
- multi method values ( %hash: Matcher $keytest? ) is export
+ multi method keys   ( %hash: ) is export
+ multi method kv     ( %hash: ) is export
+ multi method pairs  ( %hash: ) is export
+ multi method enums  ( %hash: ) is export
+ multi method values ( %hash: ) is export
 
 Iterates the elements of C<%hash>. The order is implementation dependent
 and arbitrary, but will be the same between successive calls to these
 functions, as long as C<%hash> doesn't change.
 
-If C<$keytest> is provided, only elements whose keys evaluate
-C<$key ~~ $keytest> as true are iterated.
-
 What is returned at each element of the iteration varies with function.
 C<keys> only returns the key; C<values> the value; C<kv> returns both as
 a 2 element list in (key, value) order, C<pairs> a C<Pair(key, value)>.