fix(makefile) allow strings inside $() expressions

Author: aneesh98

CHANGES.md

@@ -7,7 +7,7 @@ CAVEATS / POTENTIALLY BREAKING CHANGES
 
 Core Grammars:
 
-- Nothing yet.
+- fix(makefile) - allow strings inside `$()` expressions [aneesh98][]
 
 New Grammars:
 
@@ -24,6 +24,7 @@ Themes:
 CONTRIBUTORS
 
 [Josh Goebel]: https://github.com/joshgoebel
+[aneesh98]: https://github.com/aneesh98
 
 
 ## Version 11.10.0

src/languages/makefile.js

@@ -38,7 +38,10 @@ export default function(hljs) {
         + 'word wordlist firstword lastword dir notdir suffix basename '
         + 'addsuffix addprefix join wildcard realpath abspath error warning '
         + 'shell origin flavor foreach if or and call eval file value' },
-    contains: [ VARIABLE ]
+    contains: [ 
+      VARIABLE,
+      QUOTE_STRING // Added QUOTE_STRING as they can be a part of functions
+    ]
   };
   /* Variable assignment */
   const ASSIGNMENT = { begin: '^' + hljs.UNDERSCORE_IDENT_RE + '\\s*(?=[:+?]?=)' };