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/editor/src/indent_guides.rs

@@ -39,9 +39,13 @@ impl Editor {
     ) -> Option<Vec<MultiBufferIndentGuide>> {
         let show_indent_guides = self.should_show_indent_guides().unwrap_or_else(|| {
             if let Some(buffer) = self.buffer().read(cx).as_singleton() {
-                language_settings(buffer.read(cx).language(), buffer.read(cx).file(), cx)
-                    .indent_guides
-                    .enabled
+                language_settings(
+                    buffer.read(cx).language().map(|l| l.name()),
+                    buffer.read(cx).file(),
+                    cx,
+                )
+                .indent_guides
+                .enabled
             } else {
                 true
             }