Allow optional trailing comma in 'select'

grammar.js

@@ -145,7 +145,7 @@ module.exports = grammar({
 
     select_cases: ($) => seq(
       "{",
-      optional(commaSeparatedTrailing($.select_case)),
+      optional(commaSeparatedOptTrailing($.select_case)),
       "}",
     ),
 

src/grammar.json

@@ -614,21 +614,42 @@
           "type": "CHOICE",
           "members": [
             {
-              "type": "REPEAT",
-              "content": {
               "type": "SEQ",
               "members": [
                 {
                   "type": "SYMBOL",
                   "name": "select_case"
                 },
+                {
+                  "type": "REPEAT",
+                  "content": {
+                    "type": "SEQ",
+                    "members": [
                       {
                         "type": "STRING",
                         "value": ","
+                      },
+                      {
+                        "type": "SYMBOL",
+                        "name": "select_case"
                       }
                     ]
                   }
                 },
+                {
+                  "type": "CHOICE",
+                  "members": [
+                    {
+                      "type": "STRING",
+                      "value": ","
+                    },
+                    {
+                      "type": "BLANK"
+                    }
+                  ]
+                }
+              ]
+            },
             {
               "type": "BLANK"
             }

test/corpus/select.txt

@@ -33,6 +33,31 @@ foo = select(release_variable("RELEASE_TEST"), {
             (default))
           (unset))))))
 
+================================================================================
+Select (no trailing comma)
+================================================================================
+
+foo = select(release_variable("RELEASE_TEST"), {
+    default: unset
+})
+
+--------------------------------------------------------------------------------
+
+(source_file
+  (assignment
+    (identifier)
+    (operator)
+    (select_expression
+      (select_value
+        (condition
+          (identifier)
+          (interpreted_string_literal)))
+      (select_cases
+        (select_case
+          (select_pattern
+            (default))
+          (unset))))))
+
 ================================================================================
 Select (soong config variable)
 ================================================================================