inotify: files pointed at by multiples symlinks generate events only for one path

[hugwijst]

System details

• OS/Platform name and version: Linux 6.5.0 - Ubuntu 22.04.3
• Rust version (if building from source): rustc --version: rustc 1.75.0-nightly (0f44eb32f 2023-11-09)
• Notify version (or commit hash if building from git): 6.1.1

• If you're coming from a project that makes use of Notify, what it is, and a link to the downstream issue if there is one: buck2 (https://buck2.build)
• Filesystem type and options: ext4
• On Linux: Kernel version: 6.5.0

What you did (as detailed as you can)

I have a directory structure similar to the following:

- root
| - common
| | - file.json
| - tests
| | - test_1
| | | - common -> ../../common

We put a recursive watch on root, and then modify root/common/file.json.

What you expected

Either one of:

• Notify events for both root/common/file.json and root/tests/test_1/common/file.json.
• Notify events for just root/common/file.json

What happened

Only a notify event is fired for root/tests/test_1/common/file.json.

[hugwijst]

Relates to #255, #291, and #381, but seems distinct.

Reading https://docs.rs/inotify/latest/inotify/struct.Watches.html#attention-updating-watches-and-hardlinks, possibly the easiest way to solve this behavior is to keep a list of paths for each WatchDescriptor and add to that list at- https://github.com/notify-rs/notify/blob/main/notify/src/inotify.rs#L454.