Fix highlighting of prefix(…) inside theme(…)

Author: thecrypticace

packages/tailwindcss-language-syntax/tests/syntax.test.ts

@@ -144,16 +144,17 @@ test('@import + theme()', async ({ expect }) => {
                                                  ^  1: punctuation.terminator.rule.css
 
     @import './test.css' theme(prefix(tw) inline);
-    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 13: source.css.tailwind meta.at-rule.import.css
+    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 17: source.css.tailwind meta.at-rule.import.css
     ^^^^^^^                                         2: keyword.control.at-rule.import.css
     ^                                               1: punctuation.definition.keyword.css
             ^^^^^^^^^^^^                            3: string.quoted.single.css
             ^                                       1: punctuation.definition.string.begin.css
                        ^                            1: punctuation.definition.string.end.css
                          ^^^^^                      1: support.function.theme.css
-                              ^                     1: punctuation.section.function.begin.bracket.round.css
-                               ^^^^^^^^^            1: invalid.illegal.invalid-source.css
-                                        ^           1: punctuation.section.function.end.bracket.round.css
+                              ^      ^              2: punctuation.section.function.begin.bracket.round.css
+                               ^^^^^^               1: support.function.prefix.css
+                                      ^^ ^^^^^^^    3: variable.other.css
+                                        ^       ^   2: punctuation.section.function.end.bracket.round.css
                                                  ^  1: punctuation.terminator.rule.css
     "
   `)

packages/vscode-tailwindcss/syntaxes/at-rules.tmLanguage.json

@@ -652,6 +652,9 @@
               "match": "deprecated",
               "name": "variable.other.css"
             },
+            {
+              "include": "#prefix-meta-fn"
+            },
             {
               "match": "[^)\\s]+",
               "name": "invalid.illegal.invalid-source.css"