Search process indicator on empty query #1255

Describe the bug
The search progress bar doesn't stop moving once text has been entered and is cleared.

To Reproduce
Steps to reproduce the behavior:

1. Go to https://docs.requarks.io/releases (or any other wiki.js installation)
2. Type some arbitrary search term (e.g. Linux) into the search box
3. Press enter (Idk if this is really necessary)
4. Clear entered text from the search box
   Note: Clear the text all at once either by using CTRL+Backspace or by selecting the text and deleting it.
5. Observe the "ongoing search" animation whilst the search box is empty
   Also: If you now enter any search term it will always report back "No pages matching your query."

Expected behavior
I expect the search process to stop once the search box is emptied.
Idk if this is just the animation or if there's actually a search ongoing whilst the box is empty.

Further suggestion for enhancing the search
If I click with the mouse into the search box it shouldn't display "No pages matching your query."
Rather something like "Start typing to start a search" - this seems more user-friendly IMO.

Thanks!