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/gitcommit/config.toml

@@ -0,0 +1,12 @@
+name = "Git Commit"
+grammar = "git_commit"
+path_suffixes = [
+  # Refer to https://github.com/neovim/neovim/blob/master/runtime/lua/vim/filetype.lua#L1286-L1290
+  "TAG_EDITMSG",
+  "MERGE_MSG",
+  "COMMIT_EDITMSG",
+  "NOTES_EDITMSG",
+  "EDIT_DESCRIPTION",
+]
+line_comments = ["#"]
+brackets = []

crates/languages/src/gitcommit/highlights.scm

@@ -0,0 +1,34 @@
+(comment) @comment
+(generated_comment) @comment
+(title) @text.title
+(text) @text
+(branch) @text.reference
+(change) @keyword
+(filepath) @text.uri
+(arrow) @punctuation.delimiter
+
+(subject) @text.title
+(subject (overflow) @text)
+(prefix (type) @keyword)
+(prefix (scope) @parameter)
+(prefix [
+    "("
+    ")"
+    ":"
+] @punctuation.delimiter)
+(prefix [
+    "!"
+] @punctuation.special)
+
+(message) @text
+
+(trailer (token) @keyword)
+(trailer (value) @text)
+
+(breaking_change (token) @text.warning)
+(breaking_change (value) @text)
+
+(scissor) @comment
+(subject_prefix) @keyword
+
+(ERROR) @error

crates/languages/src/gitcommit/injections.scm

@@ -0,0 +1,8 @@
+((diff) @injection.content
+ (#set! injection.combined)
+ (#set! injection.language "diff"))
+
+((rebase_command) @injection.content
+ (#set! injection.combined)
+ (#set! injection.language "git_rebase"))
+