fix(lsp): guard linked_editing_range refresh on attach (#40888)

Problem:
on_attach() calls refresh(), but there is no guarantee the attached
buffer is the current buffer. This can make linked editing request
handling assume the wrong window.

Solution:
Call refresh() only if the current buffer is attached. This keeps the
initial highlighting behavior while avoiding making incorrect request.

runtime/lua/vim/lsp/linked_editing_range.lua

@@ -195,7 +195,9 @@ function LinkedEditor:on_attach(client_id)
     self.client_state[client_id] = state
   end
 
-  self:refresh()
+  if self.bufnr == api.nvim_get_current_buf() then
+    self:refresh()
+  end
 end
 
 ---@package