5ee72c40e2
Neovim adds a `diagnostic = { link_severity = 'warn' }` default so the value
is actually included in the payload. Vim reads the flat g:nuwiki_link_severity
global and nests it into the same `diagnostic` dict, keeping the two clients'
server-bound payloads identical.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>