rplugin: resolve paths in manifest file (#5501)

`:CheckHealth nvim` would always report an outdated manifest if symlinks were
used, because the manifest file contains unresolved paths that get compared
against resolved paths.

Now we resolve paths before they get written to the manifest file.

runtime/autoload/remote/host.vim

@@ -190,7 +190,7 @@ function! s:RegistrationCommands(host) abort
   call remote#host#RegisterClone(host_id, a:host)
   let pattern = s:plugin_patterns[a:host]
   let paths = globpath(&rtp, 'rplugin/'.a:host.'/'.pattern, 0, 1)
-  let paths = map(paths, 'tr(v:val,"\\","/")') " Normalize slashes #4795
+  let paths = map(paths, 'tr(resolve(v:val),"\\","/")') " Normalize slashes #4795
   let paths = uniq(sort(paths))
   if empty(paths)
     return []