Use syntax symbol pickers for Erlang

Neither language server robustly supports workspace symbol search.
`erlang-ls`'s symbol picker takes a long time to open successfully on
boot. `elp`'s is faster but not faster than the tags query.

languages.toml

@@ -2047,7 +2047,10 @@ roots = ["rebar.config"]
 shebangs = ["escript"]
 comment-token = "%%"
 indent = { tab-width = 4, unit = "    " }
-language-servers = [ "erlang-ls", "elp" ]
+language-servers = [
+  { name = "erlang-ls", except-features = ["document-symbols", "workspace-symbols"] },
+  { name = "elp", except-features = ["document-symbols", "workspace-symbols"] }
+]
 
 [[grammar]]
 name = "erlang"