Add OCaml support (#6929)

This pull request implements support for the [OCaml
Language](https://ocaml.org/).

### Additions
- [x]
[tree-sitter-ocaml](https://github.com/tree-sitter/tree-sitter-ocaml)
grammar
- [x] Highlight, Indents, Outline queries
- [x] A new file icon for .ml(i) files. Based on
[ocaml/ocaml-logo](https://github.com/ocaml/ocaml-logo/blob/master/Colour/SVG/colour-transparent-icon.svg)
- [x] LSP Integration with
[ocaml-language-server](https://github.com/ocaml/ocaml-lsp)
- [x] Completion Labels
- [x] Symbol Labels

### Bug Fixes
- [x] Improper parsing of LSP headers. 

### Missing [will file a separate issue]
- Documentation on completionItem, requires: `completionItem/resolve`
with support for `documentation` as a provider.

### Screenshots

<details><summary>Zed</summary>
<img width="1800" alt="Screenshot 2024-02-01 at 03 33 20"
src="https://github.com/zed-industries/zed/assets/69181766/e17c184e-203e-40c3-a08f-4de46226b79c">
</details>

Release Notes:
- Added OCaml Support
([#5316](https://github.com/zed-industries/zed/issues/5316)).

> [!NOTE]
> Partially completes #5316 
> To complete #5316:
> 1. addition of a reason tree-sitter grammar.
> 2. opam/esy integration, however it may be better as it's own plugin.

crates/zed/src/languages/ocaml-interface/brackets.scm

@@ -0,0 +1,6 @@
+("(" @open ")" @close)
+("{" @open "}" @close)
+("<" @open ">" @close)
+
+("sig" @open "end" @close)
+("object" @open "end" @close)

crates/zed/src/languages/ocaml-interface/config.toml

@@ -0,0 +1,13 @@
+name = "OCaml Interface"
+path_suffixes = ["mli"]
+block_comment = ["(* ", "*)"]
+autoclose_before = ";,=)}"
+brackets = [
+  { start = "{", end = "}", close = true, newline = true },
+  { start = "<", end = ">", close = true, newline = true },
+  { start = "[", end = "]", close = true, newline = true },
+  { start = "(", end = ")", close = true, newline = true },
+  { start = "sig", end = " end", close = true, newline = true },
+  # HACK: For some reason `object` alone does not work  
+  { start = "object ", end = "end", close = true, newline = true },
+]

crates/zed/src/languages/ocaml-interface/highlights.scm

@@ -0,0 +1 @@
+../ocaml/highlights.scm

crates/zed/src/languages/ocaml-interface/indents.scm

@@ -0,0 +1,21 @@
+[
+  (type_binding)
+
+  (value_specification)
+  (method_specification)
+
+  (external)
+  (field_declaration)
+] @indent
+
+(_ "<" ">" @end) @indent
+(_ "{" "}" @end) @indent
+(_ "(" ")" @end) @indent
+
+(_ "object" @start "end" @end) @indent
+
+(signature
+  "sig" @start
+  "end" @end) @indent
+
+";;" @outdent

crates/zed/src/languages/ocaml-interface/outline.scm

@@ -0,0 +1,48 @@
+(module_type_definition
+  "module" @context
+  "type" @context
+  name: (_) @name) @item
+
+(module_definition
+    "module" @context
+    (module_binding name: (_) @name)) @item
+
+(type_definition
+    "type" @context
+    (type_binding name: (_) @name)) @item
+
+(class_definition
+    "class" @context
+    (class_binding
+      "virtual"? @context
+      name: (_) @name)) @item
+
+(class_type_definition
+  "class" @context
+  "type" @context
+  (class_type_binding
+    "virtual"? @context
+    name: (_) @name)) @item
+
+(instance_variable_definition
+  "val" @context
+  "method"? @context
+  name: (_) @name) @item
+
+(method_specification
+  "method" @context
+  "virtual"? @context
+   (method_name) @name) @item
+
+(value_specification
+    "val" @context
+    (value_name) @name) @item
+
+(external
+  "external" @context
+  (value_name) @name) @item
+
+(exception_definition
+    "exception" @context
+    (constructor_declaration
+      (constructor_name) @name)) @item