Speed up string parsing around 100 times

The problem was that the Match.caps is using sort(), which is quite slow
which  becomes annoying when you have over 1000 json strings in your
json file.

Kudos to jnthn++ for figuring this out.

lib/JSON/Tiny/Actions.pm

@@ -23,7 +23,7 @@ method array($/) {
 }
 
 method string($/) {
-    make join '', $/.caps>>.value>>.ast
+    make join '', $0.list.map({ (.<str> || .<str_escape>).ast });
 }
 method value:sym<number>($/) { make eval $/.Str }
 method value:sym<string>($/) { make $<string>.ast }

lib/JSON/Tiny/Grammar.pm

@@ -22,7 +22,7 @@ token value:sym<array>   { <array>  };
 token value:sym<string>  { <string> }
 
 token string {
-    \" ~ \" [ <str> | \\ <str_escape> ]*
+    \" ~ \" ( <str> | \\ <str_escape> )*
 }
 
 token str {