Derive Document language name from languages.toml name key (#3338)

* Derive Document language name from `languages.toml` `name` key

This changes switches from deriving the language name from the
`languages.toml` `scope` key to `name` (`language_id` in the
`LanguageConfiguration` type). For the most part it works to derive the
language name from scope by chopping off `source.` or `rsplit_once` on
`.` but for some languages we have now like html (`text.html.basic`),
it doesn't. This also should be a more accurate fallback for the
`language_id` method which is used in LSP and currently uses the
`rsplit_once` strategy.

Here we expose the language's name as `language_name` on `Document` and
replace ad-hoc calculations of the language name with the new method.

This is most impactful for the `file-type` statusline element which is
using `language_id`.

* Use `Document::language_name` for the `file-type` statusline element

The `file-type` indicator element in the statusline was using
`Document::language_id` which is meant to be used to for telling
Language Servers what language we're using. That works for languages
with `language-server` configurations in `languages.toml` but shows
text otherwise. The new `Document::language_name` method from the
parent commit is a more accurate way to determine the language.

1 files changed, 13 insertions, 3 deletions

diff --git a/helix-view/src/document.rs b/helix-view/src/document.rs
index c96f222d..0668e99d 100644
--- a/helix-view/src/document.rs
+++ b/helix-view/src/document.rs
@@ -926,22 +926,32 @@ impl Document {
     }
 
     /// Corresponding language scope name. Usually `source.<lang>`.
-    pub fn language(&self) -> Option<&str> {
+    pub fn language_scope(&self) -> Option<&str> {
         self.language
             .as_ref()
             .map(|language| language.scope.as_str())
     }
 
+    /// Language name for the document. Corresponds to the `name` key in
+    /// `languages.toml` configuration.
+    pub fn language_name(&self) -> Option<&str> {
+        self.language
+            .as_ref()
+            .map(|language| language.language_id.as_str())
+    }
+
     /// Language ID for the document. Either the `language-id` from the
     /// `language-server` configuration, or the document language if no
     /// `language-id` has been specified.
     pub fn language_id(&self) -> Option<&str> {
-        self.language_config()?
+        let language_config = self.language.as_deref()?;
+
+        language_config
             .language_server
             .as_ref()?
             .language_id
             .as_deref()
-            .or_else(|| Some(self.language()?.rsplit_once('.')?.1))
+            .or(Some(language_config.language_id.as_str()))
     }
 
     /// Corresponding [`LanguageConfiguration`].