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/languages/src/css/config.toml

@@ -11,4 +11,3 @@ brackets = [
 ]
 word_characters = ["-"]
 block_comment = ["/* ", " */"]
-prettier_parser_name = "css"