Completion disappears if only 1 match

[jn64]

• Wordbook version: 0.4.0 (Flathub)
• Python version: Flatpak bundled (3.11?)
• Operating System: Fedora 38

Description

With Live Search disabled, the completion dropdown disappears if there is only 1 remaining candidate, which seems counterintuitive.

What I Did

1. Disable Live Search
2. Type unsa
   • There should be a dropdown with ~10 completion candidates
3. Continue typing f
   • Expected: show the only candidate unsafe so I can click it or press down+Enter
   • Actual: no completion shown, I have to manually type the rest of the word (in this case only 1 letter, but it might be longer, or a word that I can't spell)

[mufeedali]

Need to replace use of GtkEntryCompletion.

Relevant: https://gitlab.gnome.org/GNOME/gtk/-/issues/5689