Autodetect parser name with prettier by default (#11558)

Closes https://github.com/zed-industries/zed/issues/11517 

* Removes forced prettier parser name for languages, making `auto`
command to run prettier on every file by default.
* Moves prettier configs away from plugin language declarations into
language settings

Release Notes:

- N/A

crates/language/src/buffer.rs

@@ -479,6 +479,7 @@ pub struct Chunk<'a> {
 }
 
 /// A set of edits to a given version of a buffer, computed asynchronously.
+#[derive(Debug)]
 pub struct Diff {
     pub(crate) base_version: clock::Global,
     line_ending: LineEnding,