patch 8.2.2341: expresison command line completion incomplete after "g:"

Problem:    Expresison command line completion shows variables but not
            functions after "g:". (Gary Johnson)
Solution:   Prefix "g:" when needed to a global function.
diff --git a/src/evalvars.c b/src/evalvars.c
index 644190f..155f603 100644
--- a/src/evalvars.c
+++ b/src/evalvars.c
@@ -1952,7 +1952,7 @@
 /*
  * Function to concatenate a prefix and a variable name.
  */
-    static char_u *
+    char_u *
 cat_prefix_varname(int prefix, char_u *name)
 {
     int		len;