Improve documentation for ArrayList, ArrayListUnmanaged, etc. (ziglang#7624)

* Improve ArrayList & co documentation

- Added doc comments about the validity of references to elements in
an ArrayList and how they may become invalid after resizing operations.
- This should help users avoid footguns in future.

* Improve ArrayListUnmanaged & co's documentation

- Port improved documentation from ArrayList and ArrayList aligned to
  their unmanaged counterparts.
- Made documentation for ArrayListUnmanaged & co more inclusive and
  up-to-date.
- Made documentation more consistent with `ArrayList`.

* Corrections on ArrayList documentation.

- Remove incorrect/unpreferred wording on ArrayList vs
  ArrayListUnmanaged.
- Fix notes about the alignment of ArrayListAligned
- Be more verbose with warnings on when pointers are invalidated.
- Copy+paste a few warnings

* add warning to replaceRange

* revert changes to append documentation

Author: camconn