The `fish_add_path` function is only available for fish 3.2.0 or newer, and not on older versions. This commit adds an alternative way to update the PATH when `fish_add_path` does not exist.
The `fish_add_path` function is only available for fish 3.2.0 or newer, and not on older versions. This commit adds an alternative way to update the PATH when `fish_add_path` does not exist.