Support ocaml-language-server out of the box (#149)

Copyright-paperwork-exempt: yes

* eglot.el (eglot-server-programs): Add ocaml-language-server.

* README.md (Installation and usage): Mention ocaml-language-server

README.md

@@ -35,6 +35,7 @@ for the language of your choice. Otherwise, it prompts you to enter one:
 * Haskell's [IDE engine][haskell-ide-engine]
 * Kotlin's [kotlin-language-server][kotlin-language-server]
 * Golang's [go-langserver][go-langserver]
+* Ocaml's [ocaml-language-server][ocaml-language-server]
 
 I'll add to this list as I test more servers. In the meantime you can
 customize `eglot-server-programs`:
@@ -303,4 +304,4 @@ Under the hood:
 [kotlin-language-server]: https://github.com/fwcd/KotlinLanguageServer
 [go-langserver]: https://github.com/sourcegraph/go-langserver
 [eclipse-jdt]: https://github.com/eclipse/eclipse.jdt.ls
-
+[ocaml-language-server]: https://github.com/freebroccolo/ocaml-language-server

eglot.el

@@ -85,6 +85,8 @@
                                   rjsx-mode) . ("javascript-typescript-stdio"))
                                 (sh-mode . ("bash-language-server" "start"))
                                 ((c++-mode c-mode) . ("ccls"))
+                                ((caml-mode tuareg-mode reason-mode)
+                                 . ("ocaml-language-server" "--stdio"))
                                 (ruby-mode
                                  . ("solargraph" "socket" "--port"
                                     :autoport))