style: change the format of a debugging function

[Akim Demaille]

commit 7fe9205b9f58a7235721ba63c0f80ad009eba2b5
Author: Akim Demaille <akim.demaille@gmail.com>
Date:   Sun Nov 22 11:32:23 2020 +0100

    style: change the format of a debugging function
    
    * src/symlist.c (symbol_list_syms_print): Use braces to make traces
    easier to read.

diff --git a/src/symlist.c b/src/symlist.c
index 55c1fb6b..f3bc12bc 100644
--- a/src/symlist.c
+++ b/src/symlist.c
@@ -96,23 +96,24 @@ symbol_list_type_set (symbol_list *syms, uniqstr type_name)
 `-----------------------------------------------------------------------*/
 
 void
-symbol_list_syms_print (const symbol_list *l, FILE *f)
+symbol_list_syms_print (const symbol_list *l, FILE *out)
 {
-  fputc ('[', f);
+  fputc ('[', out);
   char const *sep = "";
   for (/* Nothing. */; l && l->content.sym; l = l->next)
     {
-      fputs (sep, f);
-      fputs (l->content_type == SYMLIST_SYMBOL ? "symbol: "
-             : l->content_type == SYMLIST_TYPE ? "type: "
-             : "invalid content_type: ",
-             f);
+      fputs (sep, out);
+      fputs (l->content_type == SYMLIST_SYMBOL ? "symbol{"
+             : l->content_type == SYMLIST_TYPE ? "type{"
+             : "invalid content_type{",
+             out);
       if (l->content_type == SYMLIST_SYMBOL)
-        symbol_print (l->content.sym, f);
-      fputs (l->action_props.is_value_used ? " (used)" : " (unused)", f);
+        symbol_print (l->content.sym, out);
+      fputs (l->action_props.is_value_used ? " (used)" : " (unused)", out);
+      putc ('}', out);
       sep = ", ";
     }
-  fputc (']', f);
+  fputc (']', out);
 }