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/php/embedding.scm

@@ -0,0 +1,36 @@
+(
+    (comment)* @context
+    .
+    [
+        (function_definition
+            "function" @name
+            name: (_) @name
+            body: (_
+                "{" @keep
+                "}" @keep) @collapse
+            )
+
+        (trait_declaration
+            "trait" @name
+            name: (_) @name)
+
+        (method_declaration
+            "function" @name
+            name: (_) @name
+            body: (_
+                "{" @keep
+                "}" @keep) @collapse
+            )
+
+        (interface_declaration
+            "interface" @name
+            name: (_) @name
+            )
+
+        (enum_declaration
+            "enum" @name
+            name: (_) @name
+            )
+
+        ] @item
+    )