The change in #4441 broke the handling of the `elsif`s due to the
change in logic. As every block here has a `next` there's no need to do
an `elsif` in here at all. Additionally, reorder the conditions in here
so you get an appropriate message depending on what you're trying to do.
Finally, tweak some of the messaging to remove things that are ignored
and tell people correct commands to run to link things.
We have an awful lot of integration tests and they are (comparatively)
really slow. Let's kill those that test edge case conditions and focus
on those that test that our functionality works as expected. Edge cases
can be better tested with unit tests.
Commit 4cae6a724e6d684eb157dd6d7328755694f228b2 introduced the message,
but it printed the wrong path, e.g. for `brew link sqlite`:
```
If you need to have this software first in your PATH instead consider running:
echo 'export PATH="/usr/local/opt/sqlite:$PATH"' >> ~/.zshrc/bin
```
where `/bin` is appended at the end, but should be inserted before
`:$PATH`: `echo 'export PATH="/usr/local/opt/sqlite/bin:$PATH"' >> ~/.zshrc`.
This patch fixes that and updates a test to verify it.
