Fix ruby-lsp-check raising when server message itself is an error (#…

…2659)

Fix `ruby-lsp-check` raising when server message is error

The hash must be`String => StandardError` since at the end it calls `message` on it already.

```rb
$ bundle exec ruby-lsp-check
/home/earlopain/.rbenv/versions/3.3.5/lib/ruby/3.3.0/json/common.rb:3: warning: ostruct was loaded from the standard library, but will no longer be part of the default gems starting from Ruby 3.5.0.
You can add ostruct to your Gemfile or gemspec to silence this warning.
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Indexed 2015/2015
/home/earlopain/.rbenv/versions/3.3.5/lib/ruby/gems/3.3.0/gems/ruby-lsp-0.19.0/exe/ruby-lsp-check:66:in `block in <top (required)>': undefined method `message' for an instance of String (NoMethodError)

  #{errors.map { |file, error| "#{file}: #{error.message}" }.join("\n")}
                                                ^^^^^^^^
        from /home/earlopain/.rbenv/versions/3.3.5/lib/ruby/gems/3.3.0/gems/ruby-lsp-0.19.0/exe/ruby-lsp-check:66:in `each'
        from /home/earlopain/.rbenv/versions/3.3.5/lib/ruby/gems/3.3.0/gems/ruby-lsp-0.19.0/exe/ruby-lsp-check:66:in `map'
        from /home/earlopain/.rbenv/versions/3.3.5/lib/ruby/gems/3.3.0/gems/ruby-lsp-0.19.0/exe/ruby-lsp-check:66:in `<top (required)>'
        from /home/earlopain/.rbenv/versions/3.3.5/lib/ruby/gems/3.3.0/bin/ruby-lsp-check:25:in `load'
        from /home/earlopain/.rbenv/versions/3.3.5/lib/ruby/gems/3.3.0/bin/ruby-lsp-check:25:in `<top (required)>'
        from /home/earlopain/.rbenv/versions/3.3.5/lib/ruby/site_ruby/3.3.0/bundler/cli/exec.rb:58:in `load'
        from /home/earlopain/.rbenv/versions/3.3.5/lib/ruby/site_ruby/3.3.0/bundler/cli/exec.rb:58:in `kernel_load'
        from /home/earlopain/.rbenv/versions/3.3.5/lib/ruby/site_ruby/3.3.0/bundler/cli/exec.rb:23:in `run'
        from /home/earlopain/.rbenv/versions/3.3.5/lib/ruby/site_ruby/3.3.0/bundler/cli.rb:455:in `exec'
        from /home/earlopain/.rbenv/versions/3.3.5/lib/ruby/site_ruby/3.3.0/bundler/vendor/thor/lib/thor/command.rb:28:in `run'
        from /home/earlopain/.rbenv/versions/3.3.5/lib/ruby/site_ruby/3.3.0/bundler/vendor/thor/lib/thor/invocation.rb:127:in `invoke_command'
        from /home/earlopain/.rbenv/versions/3.3.5/lib/ruby/site_ruby/3.3.0/bundler/vendor/thor/lib/thor.rb:527:in `dispatch'
        from /home/earlopain/.rbenv/versions/3.3.5/lib/ruby/site_ruby/3.3.0/bundler/cli.rb:35:in `dispatch'
        from /home/earlopain/.rbenv/versions/3.3.5/lib/ruby/site_ruby/3.3.0/bundler/vendor/thor/lib/thor/base.rb:584:in `start'
        from /home/earlopain/.rbenv/versions/3.3.5/lib/ruby/site_ruby/3.3.0/bundler/cli.rb:29:in `start'
        from /home/earlopain/.rbenv/versions/3.3.5/lib/ruby/gems/3.3.0/gems/bundler-2.5.20/exe/bundle:28:in `block in <top (required)>'
        from /home/earlopain/.rbenv/versions/3.3.5/lib/ruby/site_ruby/3.3.0/bundler/friendly_errors.rb:117:in `with_friendly_errors'
        from /home/earlopain/.rbenv/versions/3.3.5/lib/ruby/gems/3.3.0/gems/bundler-2.5.20/exe/bundle:20:in `<top (required)>'
        from /home/earlopain/.rbenv/versions/3.3.5/bin/bundle:25:in `load'
        from /home/earlopain/.rbenv/versions/3.3.5/bin/bundle:25:in `<main>'
```

exe/ruby-lsp-check

@@ -32,7 +32,7 @@ files.each_with_index do |file, index|
   })
 
   result = server.pop_response
-  errors[file] = result.message if result.is_a?(RubyLsp::Error)
+  errors[file] = result if result.is_a?(RubyLsp::Error)
 ensure
   server.process_message({ method: "textDocument/didClose", params: { textDocument: { uri: uri } } })
   server.pop_response