Use a single action for toggling the language (#21331)

Follow-up of https://github.com/zed-industries/zed/pull/21299

Release Notes:

- N/A

crates/language_selector/src/active_buffer_language.rs

@@ -4,9 +4,7 @@ use language::LanguageName;
 use ui::{Button, ButtonCommon, Clickable, FluentBuilder, LabelSize, Tooltip};
 use workspace::{item::ItemHandle, StatusItemView, Workspace};
 
-use crate::LanguageSelector;
-
-gpui::actions!(language_selector, [Toggle]);
+use crate::{LanguageSelector, Toggle};
 
 pub struct ActiveBufferLanguage {
     active_language: Option<Option<LanguageName>>,