Don't allow whitespace inside of string literals

grammar.js

@@ -677,7 +677,7 @@ module.exports = grammar({
       '\'',
       choice(
         $.escape_sequence,
-        /[^\n']/
+        token.immediate(/[^\n']/)
       ),
       '\''
     ),
@@ -690,13 +690,13 @@ module.exports = grammar({
     string_literal: $ => seq(
       '"',
       repeat(choice(
-        token(prec(1, /[^\\"\n]/)),
+        token.immediate(prec(1, /[^\\"\n]/)),
         $.escape_sequence
       )),
       '"'
     ),
 
-    escape_sequence: $ => token(seq(
+    escape_sequence: $ => token.immediate(seq(
       '\\',
       choice(
         /[^xuU]/,

src/grammar.json

@@ -4027,8 +4027,11 @@
               "name": "escape_sequence"
             },
             {
-              "type": "PATTERN",
-              "value": "[^\\n']"
+              "type": "IMMEDIATE_TOKEN",
+              "content": {
+                "type": "PATTERN",
+                "value": "[^\\n']"
+              }
             }
           ]
         },
@@ -4067,7 +4070,7 @@
             "type": "CHOICE",
             "members": [
               {
-                "type": "TOKEN",
+                "type": "IMMEDIATE_TOKEN",
                 "content": {
                   "type": "PREC",
                   "value": 1,
@@ -4091,7 +4094,7 @@
       ]
     },
     "escape_sequence": {
-      "type": "TOKEN",
+      "type": "IMMEDIATE_TOKEN",
       "content": {
         "type": "SEQ",
         "members": [