docs: add note for wsl users about filesystem location. (#6101) (#6109)

(cherry picked from commit 2e05f75)

Co-authored-by: Bhumil Mayani <[email protected]>
Co-authored-by: Tomoya Fujita <[email protected]>

Author: 3 people

README.md

@@ -70,3 +70,9 @@ To test building the multisite version deployed to the website use:
 `sensible-browser build/html/rolling/index.html`
 
 **NB:** This will ignore local workspace changes and build from the branches.
+
+### Note for Windows (WSL) Users
+
+When building the documentation on windows using WSL, it is recommended to clone and work with this repository inside the Linux filesystem (for example, under `/home/<user>/`) rather than under `/mnt/c`.
+
+Working under `/mnt/c` can lead to slower builds and filesystem-related issues with Sphinx and ROS tooling.