feature(lsp): add [Text_document.position_encoding] (#1072)

Signed-off-by: Rudi Grinberg <[email protected]>

Author: rgrinberg

lsp/src/text_document.ml

@@ -29,6 +29,8 @@ type t =
   ; position_encoding : [ `UTF8 | `UTF16 ]
   }
 
+let position_encoding t = t.position_encoding
+
 let make ~position_encoding
     { DidOpenTextDocumentParams.textDocument =
         { TextDocumentItem.languageId; text; uri; version }

lsp/src/text_document.mli

@@ -9,6 +9,8 @@ val languageId : t -> string
 
 val documentUri : t -> Uri0.t
 
+val position_encoding : t -> [ `UTF16 | `UTF8 ]
+
 val version : t -> int
 
 val text : t -> string