remove solargraph config

lua/lsp.lua

@@ -67,9 +67,6 @@ servers.on_server_ready(function(server)
   if server.name == "rust_analyzer" then
     config.settings = require'lsp.rust'
   end
-  if server.name == "solargraph" then
-    server.cmd = "solargraph"
-  end
   server:setup(config)
 end)