openocd: rewrite command 'version' as COMMAND_HANDLER

Trivial change.
While there:
- add the mandatory 'usage' field;
- document the optional parameter 'git';
- reword the documentation.

Change-Id: I6be4d4423128fa026a62e2ef355f77b69d50397e
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-on: https://review.openocd.org/c/openocd/+/7488
Tested-by: jenkins

src/openocd.c

@@ -51,24 +51,23 @@ static const char openocd_startup_tcl[] = {
 };
 
 /* Give scripts and TELNET a way to find out what version this is */
-static int jim_version_command(Jim_Interp *interp, int argc,
-	Jim_Obj * const *argv)
+COMMAND_HANDLER(handler_version_command)
 {
-	if (argc > 2)
-		return JIM_ERR;
-	const char *str = "";
-	char *version_str;
-	version_str = OPENOCD_VERSION;
+	char *version_str = OPENOCD_VERSION;
 
-	if (argc == 2)
-		str = Jim_GetString(argv[1], NULL);
+	if (CMD_ARGC > 1)
+		return ERROR_COMMAND_SYNTAX_ERROR;
+
+	if (CMD_ARGC == 1) {
+		if (strcmp("git", CMD_ARGV[0]))
+			return ERROR_COMMAND_ARGUMENT_INVALID;
 
-	if (strcmp("git", str) == 0)
 		version_str = GITVERSION;
+	}
 
-	Jim_SetResult(interp, Jim_NewStringObj(interp, version_str, -1));
+	command_print(CMD, "%s", version_str);
 
-	return JIM_OK;
+	return ERROR_OK;
 }
 
 static int log_target_callback_event_handler(struct target *target,
@@ -194,9 +193,10 @@ COMMAND_HANDLER(handle_add_script_search_dir_command)
 static const struct command_registration openocd_command_handlers[] = {
 	{
 		.name = "version",
-		.jim_handler = jim_version_command,
+		.handler = handler_version_command,
 		.mode = COMMAND_ANY,
 		.help = "show program version",
+		.usage = "[git]",
 	},
 	{
 		.name = "noinit",