Don't send "no information available" on vim.lsp.buf.hover if at least one attached server has information

[mawkler]

Problem

Currently, if you have multiple language servers attached to a buffer and at least one of them responds with no information on vim.lsp.buf.hover the message "no information available" is sent.

Expected behavior

The message "no information available" is only sent if none of the servers responded with hover information.

[crwebb85]

I was looking at the hover code the other day, and it appeared to me it would send the request to both, and based on the look, I expected the last response to win