Add comments

For now it only supports non-nested comments. It seems like I *will*
need to write an external lexer to account for nesting properly.

src/grammar.json

@@ -23,6 +23,34 @@
         }
       ]
     },
+    "comment": {
+      "type": "TOKEN",
+      "content": {
+        "type": "SEQ",
+        "members": [
+          {
+            "type": "STRING",
+            "value": "/*"
+          },
+          {
+            "type": "REPEAT",
+            "content": {
+              "type": "CHOICE",
+              "members": [
+                {
+                  "type": "PATTERN",
+                  "value": "(\\*[^/]|[^*])+"
+                }
+              ]
+            }
+          },
+          {
+            "type": "STRING",
+            "value": "*/"
+          }
+        ]
+      }
+    },
     "_expr": {
       "type": "CHOICE",
       "members": [
@@ -1426,7 +1454,11 @@
   "extras": [
     {
       "type": "PATTERN",
-      "value": "\\s"
+      "value": "( |\\n|\\r|\\t)+"
+    },
+    {
+      "type": "SYMBOL",
+      "name": "comment"
     }
   ],
   "conflicts": [

src/node-types.json

@@ -2283,6 +2283,10 @@
     "type": "break_expression",
     "named": true
   },
+  {
+    "type": "comment",
+    "named": true
+  },
   {
     "type": "do",
     "named": false