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/prettier/src/prettier.rs

@@ -205,7 +205,7 @@ impl Prettier {
                 let params = buffer
                     .update(cx, |buffer, cx| {
                         let buffer_language = buffer.language();
-                        let language_settings = language_settings(buffer_language, buffer.file(), cx);
+                        let language_settings = language_settings(buffer_language.map(|l| l.name()), buffer.file(), cx);
                         let prettier_settings = &language_settings.prettier;
                         anyhow::ensure!(
                             prettier_settings.allowed,