fix(lsp): advertise that CompletionItem.detail can be resolved (#39934)

Problem:
We can resolve the `CompletionItem.detail` field but don't advertise
this capability.

Solution:
Add `detail` to
`textDocument.completion.completionItem.resolveSupport.properties`.

runtime/lua/vim/lsp/protocol.lua

@@ -483,6 +483,7 @@ function protocol.make_client_capabilities()
               'additionalTextEdits',
               'command',
               'documentation',
+              'detail',
             },
           },
           tagSupport = {