grammar: fix missing format related edge-cases (#12)

This atleast makes the parser not error, there's probably some issues in
the AST generation but that kind of problem can wait until LSP-related
integration.

Fixes #10 
Fixes #11

grammar.js

@@ -202,10 +202,11 @@ module.exports = grammar({
       /[\[\]]/,
       /[<>]/,
       ';',
+      '`',
       seq(field('numberOfArgs', $._format_token), '*'),
       '?',
       "Newline",
-      seq(repeat(choice($._format_token, ',')), /[$rRbBdDgGxXeEoOsStTfF]/),
+      seq(repeat(choice($._format_token, ',')), /[$mrRbBdDgGxXeEoOsStTfF]/),
     ),
     format_specifier: $ =>
       prec.left(seq(

package.json

@@ -6,8 +6,8 @@
   "scripts": {
     "gen": "yarn tree-sitter generate",
     "test": "yarn tree-sitter test",
-    "parse-sample": "yarn tree-sitter parse test/samples/sample.gc",
-    "parse-test": "yarn tree-sitter parse test/samples/test.gc"
+    "parse-sample": "yarn gen && yarn tree-sitter parse test/samples/sample.gc",
+    "parse-test": "yarn gen && yarn tree-sitter parse test/samples/test.gc"
   },
   "repository": {
     "type": "git",