Problem: On nvim 11.0-dev, deprecation warnings due to an use of
hard-deprecated APIs such as:
- `vim.diagnostic.disable()`
- `vim.diagnostic.is_disabled()`
etc. are not accompanied by backtrace information. It makes difficult
for users to figure out which lines or which plugins are still using
deprecated APIs.
Solution: use `backtrace = true` in vim.deprecate() call.
9a43ec13e6
