Fix rendering

The old pod grammar doesn't handle 'C«<O(I<...>)>»' well, in the
sense that it doesn't consider the inner 'I<...>' to be markup.

The RakuAST grammar does, causing difference in rendering.  Since
the I<...> is really only for a little emphasis, it feels ok to
remove that for now to get consistent rendering.

Author: lizmat

doc/Language/glossary.rakudoc

@@ -744,7 +744,7 @@ a subexpression. For example, C<@a[0]> belongs to the postcircumfix
 category, is broken into the operand C<@a> and the postcircumfix operator
 C<[0]> where C<0> is the postcircumfixed subexpression.
 
-The C«<O(I<...>)>» construction gives information about an operator
+The C«<O(...)>» construction gives information about an operator
 that completes the information provided by its category. Below
 C<%conditional> is the category, C«:reducecheck<ternary>», which
 specifies calling C<.ternary> to post-process the L<parse subtree|#Parse_tree>