Problem: After `vim.pack.update()` it is not clear if plugin is active
or not. This can be useful to detect cases when plugin was removed
from 'init.lua' but there was no `vim.pack.del()`.
Solution: Add ` (not active)` suffix with distinctive highlighting to
header of plugins that are not active.
It will also be shown in in-process LSP document symbols to have quick
reference about which plugins are not active.
Problem: In some areas plugin's revision is named "state". This might be
confusing for the users.
Solution: Consistently use "revision" to indicate "plugin's state on
disk".
