Fix navigation not working when the active verse has no text

[LAfricain]

Summary

Xiphos would not work navigation (dropdown menus, spin arrows, and the lookup entry) whenever the target verse had no text in the active module. The display stayed stuck on the previously shown reference, nothing updated, and no error was shown to the user.

Root cause

In on_entry_activate() (src/gtk/navbar_versekey.c), a key was treated as invalid if main_get_raw_text() returned fewer than 2 characters:

rawtext = main_get_raw_text(navbar_versekey.module_name->str, (gchar *)buf);
if (!rawtext || (rawtext && (strlen(rawtext) < 2))) {
    gtk_entry_set_text(entry, navbar_versekey.key->str);
    g_free(rawtext);
    return;
}

This conflates two different things:

• whether the reference is structurally valid for the module's versification (already correctly checked right after, via main_get_valid_key() / main_is_Bible_key())
• whether the module happens to have text for that specific verse

A reference can be perfectly valid while having no text (sparse/partial module, a verse intentionally left blank, etc.). BibleTime handles this correctly and simply shows an empty page. Xiphos, instead, aborted navigation entirely and got stuck.

Reproduction

1. Take any Bible module and blank out the text of verse 1 of some chapter (e.g. 1 Kings 5:1).
2. Try to navigate to that chapter, via the dropdown menu, the spin arrows, or by typing the reference directly.
3. Navigation silently fails: the navbar stays on the previous reference.

Fix

Removed the text-emptiness check. Key validity is now determined solely by main_get_valid_key() / main_is_Bible_key(), consistent with the rest of the function.

Testing

Manually verified: blanking verse 1 of a chapter previously froze navigation to that chapter entirely. After this fix, navigation works normally and an empty verse is displayed as expected, without affecting navigation to subsequent verses/chapters.

[LAfricain]

@karlkleinpaste,, I don't know if you remember that bug with 1 Kings 3:1 in the LXX. That's what this is about—it works with this PR. To get around the problem, I used to edit the OSIS files before conversion, but now that's no longer necessary.