Eliminates 'subscript adverb' category refs #1410

Author: JJ

doc/Language/subscripts.pod6

@@ -453,9 +453,10 @@ require you to add parentheses in compound expressions:
 
 The supported adverbs are:
 
-=head2 X<:exists|subscript adverb,:exists>
+X<|:exists (subscript adverb)>
+=head2 C<:exists>
 
-Return whether or not the requested element exists, instead of returning the
+Returns whether or not the requested element exists, instead of returning the
 element's actual value. This can be used to distinguish between elements with
 an undefined value, and elements that aren't part of the collection at all:
 
@@ -491,7 +492,8 @@ element I<existence>.
 See L<#method EXISTS-POS> and L<#method EXISTS-KEY> for the underlying
 mechanism.
 
-=head2 X<:delete|subscript adverb,:delete>
+X<:delete (subscript adverb)>
+=head2 C<:delete>
 
 Delete the element from the collection or, if supported by the collection,
 creates a hole at the given index, in addition to returning its value.
@@ -532,7 +534,8 @@ element will at the same time also be deleted.
 See L<#method DELETE-POS> and L<#method DELETE-KEY> for the underlying
 mechanism.
 
-=head2 X<:p|subscript adverb,:p>
+X<|:p (subscript adverb)>
+=head2 C<:p>
 
 Return both the index/key and the value of the element, in the form of a
 L<Pair>, and silently skip nonexistent elements:
@@ -555,7 +558,8 @@ Can be combined with the L<#:exists> and L<#:delete> adverbs.
 
 See also the L<pairs> routine.
 
-=head2 X<:kv|subscript adverb,:kv>
+X<:kv (subscript adverb)>
+=head2 C<:kv>
 
 Return both the index/key and the value of the element, in the form of a
 L<List>, and silently skip nonexistent elements. When used on a
@@ -588,7 +592,8 @@ Can be combined with the L<#:exists> and L<#:delete> adverbs.
 
 See also the L<kv> routine.
 
-=head2 X<:k|subscript adverb,:k>
+X<:k (subscript adverb)>
+=head2 C<:k>
 
 Return only the index/key of the element, rather than its value, and silently
 skip nonexistent elements:
@@ -609,7 +614,8 @@ If you I<don't> want to skip nonexistent elements, use the negated form:
 
 See also the L<keys> routine.
 
-=head2 X<:v|subscript adverb,:v>
+X<:v (subscript adverb)>
+=head2 C<:v>
 
 Return the bare value of the element (rather than potentially returning a
 mutable value container), and silently skip nonexistent elements: