chore: Extract languages from zed crate (#8270)

- Moves languages module from `zed` into a separate crate. That way we
have less of a long pole at the end of compilation.
- Removes moot dependencies on editor/picker. This is totally harmless
and might help in the future if we decide to decouple picker from
editor.

Before:
```
Number of crates that depend on 'picker' but not on 'editor': 1
Total number of crates that depend on 'picker': 13
Total number of crates that depend on 'editor': 30
```
After:
```
Number of crates that depend on 'picker' but not on 'editor': 5
Total number of crates that depend on 'picker': 12
Total number of crates that depend on 'editor': 26
```
The more crates depend on just picker but not editor, the better in that
case.

Release Notes:

- N/A

crates/languages/src/json/highlights.scm

@@ -0,0 +1,21 @@
+(comment) @comment
+
+(string) @string
+
+(pair
+  key: (string) @property)
+
+(number) @number
+
+[
+  (true)
+  (false)
+  (null)
+] @constant
+
+[
+  "{"
+  "}"
+  "["
+  "]"
+] @punctuation.bracket