Remove two obsolete declarations

I happened to find a couple of obsolete declarations in cli-interp.h.
This patch removes them.  Tested by rebuilding.
diff --git a/gdb/cli/cli-interp.h b/gdb/cli/cli-interp.h
index 863e8c3..1620305 100644
--- a/gdb/cli/cli-interp.h
+++ b/gdb/cli/cli-interp.h
@@ -34,10 +34,6 @@ class cli_interp_base : public interp
   bool supports_command_editing () override;
 };
 
-extern int cli_interpreter_supports_command_editing (struct interp *interp);
-
-extern void cli_interpreter_pre_command_loop (struct interp *self);
-
 /* Returns true if the current stop should be printed to
    CONSOLE_INTERP.  */
 extern int should_print_stop_to_console (struct interp *interp,