plugins: purge now unused `add_usage_hint()`

cdda and vcd were the only users, both have now been switched to use
`set_help()`.

include/vlc_plugin.h

@@ -109,7 +109,6 @@ enum vlc_module_properties
 
 /* Configuration hint types */
 #define CONFIG_HINT_CATEGORY                0x02  /* Start of new category */
-#define CONFIG_HINT_USAGE                   0x05  /* Usage information */
 
 #define CONFIG_CATEGORY                     0x06 /* Set category */
 #define CONFIG_SUBCATEGORY                  0x07 /* Set subcategory */
@@ -192,7 +191,7 @@ enum vlc_module_properties
 /**
  * Current plugin ABI version
  */
-#define VLC_API_VERSION_STRING "4.0.4"
+#define VLC_API_VERSION_STRING "4.0.5"
 
 /*****************************************************************************
  * Add a few defines. You do not want to read this section. Really.
@@ -378,9 +377,6 @@ VLC_METADATA_EXPORTS
 #define add_category_hint(text, longtext) \
     add_typedesc_inner( CONFIG_HINT_CATEGORY, text, longtext )
 
-#define add_usage_hint( text ) \
-    add_typedesc_inner( CONFIG_HINT_USAGE, text, NULL )
-
 #define add_string( name, value, text, longtext, advc ) \
     add_string_inner(CONFIG_ITEM_STRING, name, text, longtext, value)
 

src/config/help.c

@@ -361,7 +361,6 @@ static void print_item(const module_t *m, const module_config_t *item,
             switch (item->i_type)
             {
                 case CONFIG_HINT_CATEGORY:
-                case CONFIG_HINT_USAGE:
                     printf(color ? GREEN "\n %s\n" GRAY : "\n %s\n",
                            module_gettext(m, item->psz_text));
 

src/libvlc-module.c

@@ -1524,7 +1524,6 @@ static const char *const mouse_wheel_texts[] = {
  * Quick usage guide for the configuration options:
  *
  * add_category_hint(N_(text), N_(longtext))
- * add_usage_hint( N_(text), b_advanced_option )
  * add_string( option_name, value, N_(text), N_(longtext),
                b_advanced_option )
  * add_loadfile( option_name, psz_value, N_(text), N_(longtext) )