Use immediate

grammar.js

@@ -196,7 +196,7 @@ module.exports = grammar({
 				),
 
 				expansion: $ => seq(
-					'$',
+					token.immediate('$'),
 					choice(
 						$.variable,
 						seq('{', alias(/[^\}]+/, $.variable), '}'),
@@ -304,8 +304,8 @@ module.exports = grammar({
 				),
 
 				shell_fragment: $ => repeat1(choice(
-					/[^\\\[\n#\s][^\\\[\n]*/, // non-escape or newline character
-					/\\[^\n]/,                // non-line-continuation escape
+					/[^\\\[\n#\s][^\\\[\n]*/,
+					/\\[^\n]/,
 				)),
 
 				line_continuation: $ => '\\\n',

src/grammar.json

@@ -811,8 +811,11 @@
       "type": "SEQ",
       "members": [
         {
-          "type": "STRING",
-          "value": "$"
+          "type": "IMMEDIATE_TOKEN",
+          "content": {
+            "type": "STRING",
+            "value": "$"
+          }
         },
         {
           "type": "CHOICE",