Support .editorconfig (#19455)

Closes https://github.com/zed-industries/zed/issues/8534
Supersedes https://github.com/zed-industries/zed/pull/16349

Potential concerns:
* we do not follow up to the `/` when looking for `.editorconfig`, only
up to the worktree root.
Seems fine for most of the cases, and the rest should be solved
generically later, as the same issue exists for settings.json
* `fn language` in `AllLanguageSettings` is very hot, called very
frequently during rendering. We accumulate and parse all `.editorconfig`
file contents beforehand, but have to go over globs and match these
against the path given + merge the properties still.
This does not seem to be very bad, but needs more testing and
potentially some extra caching.


Release Notes:

- Added .editorconfig support

---------

Co-authored-by: Ulysse Buonomo <buonomo.ulysse@gmail.com>

crates/collab/src/tests/remote_editing_collaboration_tests.rs

@@ -3,7 +3,7 @@ use call::ActiveCall;
 use fs::{FakeFs, Fs as _};
 use gpui::{Context as _, TestAppContext};
 use http_client::BlockedHttpClient;
-use language::{language_settings::all_language_settings, LanguageRegistry};
+use language::{language_settings::language_settings, LanguageRegistry};
 use node_runtime::NodeRuntime;
 use project::ProjectPath;
 use remote::SshRemoteClient;
@@ -135,9 +135,7 @@ async fn test_sharing_an_ssh_remote_project(
     cx_b.read(|cx| {
         let file = buffer_b.read(cx).file();
         assert_eq!(
-            all_language_settings(file, cx)
-                .language(Some(&("Rust".into())))
-                .language_servers,
+            language_settings(Some("Rust".into()), file, cx).language_servers,
             ["override-rust-analyzer".to_string()]
         )
     });