patch 8.2.1423: Vim9: find global function when looking for script-local

Problem:    Vim9: find global function when looking for script-local.
Solution:   Don't strip prefix if name starts with "s:". (closes #6688)

src/testdir/test_vim9_func.vim

@@ -203,6 +203,15 @@ def Test_global_local_function()
       assert_equal('local', Func())
   END
   CheckScriptSuccess(lines)
+
+  lines =<< trim END
+      vim9script
+      def g:Funcy()
+        echo 'funcy'
+      enddef
+      s:Funcy()
+  END
+  CheckScriptFailure(lines, 'E117:')
 enddef
 
 func TakesOneArg(arg)

src/userfunc.c

@@ -2132,8 +2132,8 @@ call_func(
 		char_u *p = untrans_function_name(rfname);
 
 		// If using Vim9 script try not local to the script.
-		// TODO: should not do this if the name started with "s:".
+		// Don't do this if the name starts with "s:".
-		if (p != NULL)
+		if (p != NULL && (funcname[0] != 's' || funcname[1] != ':'))
 		    fp = find_func(p, is_global, NULL);
 	    }
 

src/version.c

@@ -754,6 +754,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1423,
 /**/
     1422,
 /**/