Simplify RakuAST::Regex::CharClassEnumerationElement::Character

It takes a single character.  No need to make that a named argument.
The name of the class is sufficient information to know what it
takes as a positional argument in .new.

Set also RakuAST.IntLiteral, RakuAST.StrLiteral, etc.

src/Raku/Actions.nqp

@@ -2815,7 +2815,7 @@ class Raku::RegexActions is HLL::Actions does Raku::CommonActions {
                 }
                 else {
                     my $node := self.r('Regex', 'CharClassEnumerationElement', 'Character');
-                    @elements.push($node.new(:character(~$_[0])));
+                    @elements.push($node.new(~$_[0]));
                 }
             }
             self.attach: $/, self.r('Regex', 'CharClassElement', 'Enumeration').new:
@@ -2900,7 +2900,7 @@ class Raku::RegexActions is HLL::Actions does Raku::CommonActions {
 
     method cclass_backslash:sym<any>($/) {
         self.attach: $/,
-            self.r('Regex', 'CharClassEnumerationElement', 'Character').new(:character(~$/));
+            self.r('Regex', 'CharClassEnumerationElement', 'Character').new(~$/);
     }
 
     method mod_internal($/) {

src/Raku/ast/regex.rakumod

@@ -1581,7 +1581,7 @@ class RakuAST::Regex::CharClassEnumerationElement::Character
 {
     has str $.character;
 
-    method new(str :$character!) {
+    method new(str $character) {
         my $obj := nqp::create(self);
         nqp::bindattr_s($obj, RakuAST::Regex::CharClassEnumerationElement::Character,
             '$!character', $character);