fix(ruby_lsp): prevent duplicate clients on second buffer

Problem: When opening multiple Ruby buffers, a second LSP client is
spawned instead of reusing the first client, even though they share
the same root directory.

Root cause: The reuse_client function sets cmd_cwd as a side effect
during reuse checks. This means the first client is created without
cmd_cwd set, causing the reuse check to fail for the second buffer.

Solution: Use before_init to ensure cmd_cwd is set for every client.
Remove the custom reuse_client function to use Neovim's default
reuse logic (compare name + root_dir).

Testing: Tested with Neovim 0.11.4 by opening 3 Ruby files. All
buffers now correctly reuse the first client.

Author: stask

lsp/ruby_lsp.lua

@@ -20,8 +20,7 @@ return {
   init_options = {
     formatter = 'auto',
   },
-  reuse_client = function(client, config)
+  before_init = function(_, config)
     config.cmd_cwd = config.root_dir
-    return client.config.cmd_cwd == config.cmd_cwd
   end,
 }