Use expr_str() to print selected/implied symbols

This is redundant on its own, as only a single symbol can be
selected/implied, meaning just .name will work fine too. It means that
all symbols appearing in the __str__() representation of symbols and
choices are now printed via expr_str() though, which might come in handy
soon.

Author: ulfalizer

kconfiglib.py

@@ -4350,13 +4350,13 @@ def indent_add(s):
 
             if isinstance(sc, Symbol):
                 for select, cond in sc.selects:
-                    select_string = "select " + select.name
+                    select_string = "select " + expr_str(select)
                     if cond is not sc.kconfig.y:
                         select_string += " if " + expr_str(cond)
                     indent_add(select_string)
 
                 for imply, cond in sc.implies:
-                    imply_string = "imply " + imply.name
+                    imply_string = "imply " + expr_str(imply)
                     if cond is not sc.kconfig.y:
                         imply_string += " if " + expr_str(cond)
                     indent_add(imply_string)