Failed to format a file containing non-ASCII UTF-8 characters

[sile]

Describe the bug

I used the formatting feature to format a file containing non-ASCII UTF-8 characters and the result contained garbled characters.

BTW, I have fixed this problem in my forked branch (sile/erlang_ls#fix-unicode-handling). So, I can create an PR if it's okay.

To Reproduce

Please format the following file using the latest erlang_ls version (v0.25.0).

-module(test).

-export([foo/0]).

foo() ->
%% 👍😀🎉
    bar.

Expected behavior

The expected result is,

-module(test).

-export([foo/0]).

foo() ->
    %% 👍😀🎉
    bar.

Actual behavior

The actual result is,

-module(test).

-export([foo/0]).

foo() ->
    %% ð\237\221\215ð\237\230\200ð\237\216\211
    bar.

Context

• erlang_ls version (tag/sha): 0.25.0
• Editor used: Emacs
• LSP client used: lsp-mode