eval: Move remaining get_tv_string* functions to eval/typval.c

src/nvim/ex_cmds.c

@@ -1008,8 +1008,8 @@ void do_bang(int addr_count, exarg_T *eap, int forceit, int do_in, int do_out)
 
     AppendToRedobuffLit(cmd, -1);
     xfree(cmd);
-    AppendToRedobuff((char_u *)"\n");
-    bangredo = FALSE;
+    AppendToRedobuff("\n");
+    bangredo = false;
   }
   /*
    * Add quotes around the command, for shells that need them.