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/editor/src/display_map/tab_map.rs

@@ -2,8 +2,8 @@ use super::{
     fold_map::{self, FoldChunks, FoldEdit, FoldPoint, FoldSnapshot},
     Highlights,
 };
-use crate::MultiBufferSnapshot;
 use language::{Chunk, Point};
+use multi_buffer::MultiBufferSnapshot;
 use std::{cmp, mem, num::NonZeroU32, ops::Range};
 use sum_tree::Bias;