docs: add wiki FAQ to the runtime documentation (#26539)

Problem: Wiki contents are not discoverable and hard to maintain.
Solution: Move FAQ to runtime docs.

Co-authored-by: Christian Clason <c.clason@uni-graz.at>

CONTRIBUTING.md

@@ -24,7 +24,7 @@ Reporting problems
 - If a specific configuration or plugin is necessary to recreate the problem, use the minimal template in `contrib/minimal.lua` with `nvim --clean -u contrib/minimal.lua` after making the necessary changes.
 - [Bisect](https://neovim.io/doc/user/starting.html#bisect) your config: disable plugins incrementally, to narrow down the cause of the issue.
 - [Bisect][git-bisect] Neovim's source code to find the cause of a regression, if you can. This is _extremely_ helpful.
-- When reporting a crash, [include a stacktrace](https://github.com/neovim/neovim/wiki/FAQ#backtrace-linux).
+- When reporting a crash, [include a stacktrace](https://neovim.io/doc/user/faq.html#backtrace-linux).
 - Use [ASAN/UBSAN](#clang-sanitizers-asan-and-ubsan) to get detailed errors for segfaults and undefined behavior.
 - Check the logs. `:edit $NVIM_LOG_FILE`
 - Include `cmake --system-information` for build-related issues.
@@ -347,4 +347,4 @@ as context, use the `-W` argument as well.
 [pr-ready]: https://docs.github.com/en/github/collaborating-with-pull-requests/proposing-changes-to-your-work-with-pull-requests/changing-the-stage-of-a-pull-request
 [run-tests]: https://github.com/neovim/neovim/blob/master/test/README.md#running-tests
 [style-guide]: https://neovim.io/doc/user/dev_style.html#dev-style
-[wiki-faq]: https://github.com/neovim/neovim/wiki/FAQ
+[wiki-faq]: https://neovim.io/doc/user/faq.html