Fixed a wrong reference to utils_open_browser()

doc/pluginsymbols.c

@@ -103,7 +103,7 @@ void plugin_init(GeanyData *data);
 void plugin_cleanup();
 
 /** Called whenever the plugin should show its documentation (if any). This may open a dialog,
- * a browser with a website or a local installed HTML help file(see utils_start_browser())
+ * a browser with a website or a local installed HTML help file(see utils_open_browser())
  * or something else.
  * Can be omitted when not needed. */
 void plugin_help();