Merge #4236

4236: Document Gnome Builder support r=matklad a=lnicola

Closes #3758.

CC @gwutz

Co-authored-by: Laurențiu Nicola <lnicola@dend.ro>

docs/user/readme.adoc

@@ -201,7 +201,7 @@ let g:LanguageClient_serverCommands = {
 
 2. Configure by adding this to your vim/neovim config file (replacing the existing Rust-specific line if it exists):
 +
-[source,vim]   
+[source,vim]
 ----
 let g:ycm_language_server =
 \ [
@@ -252,6 +252,15 @@ If it worked, you should see "rust-analyzer, Line X, Column Y" on the left side
 
 If you get an error saying `No such file or directory: 'rust-analyzer'`, see the <<rust-analyzer-language-server-binary,`rust-analyzer` binary>> section on installing the language server binary.
 
+=== Gnome Builder
+
+Prerequisites: You have installed the <<rust-analyzer-language-server-binary,`rust-analyzer` binary>>.
+
+Gnome Builder currently has support for RLS, and there's no way to configure the language server executable. A future version might support `rust-analyzer` out of the box.
+
+1. Rename, symlink or copy the `rust-analyzer` binary to `rls` and place it somewhere Builder can find (in `PATH`, or under `~/.cargo/bin`).
+2. Enable the Rust Builder plugin.
+
 == Usage
 
 See https://github.com/rust-analyzer/rust-analyzer/blob/master/docs/user/features.md[features.md].