Use g_utf8_get_char_validated
Acrostic Greeter crashes frequently due to an undefined behavior, this fixes it !
thread '<unnamed>' panicked at src/charset.rs:451:33:
called `Option::unwrap()` on a `None` value
stack backtrace:
0: rust_begin_unwind
at /rustc/07dca489ac2d933c78d3c5158e3f43beefeb02ce/library/std/src/panicking.rs:645:5
1: core::panicking::panic_fmt
at /rustc/07dca489ac2d933c78d3c5158e3f43beefeb02ce/library/core/src/panicking.rs:72:14
2: core::panicking::panic
at /rustc/07dca489ac2d933c78d3c5158e3f43beefeb02ce/library/core/src/panicking.rs:144:5
3: core::option::Option<T>::unwrap
at /rustc/07dca489ac2d933c78d3c5158e3f43beefeb02ce/library/core/src/option.rs:931:21
4: ipuz_charset_get_char_count
at /home/tanmay/Desktop/projects/gnome/libipuz/libipuz/rust/src/charset.rs:451:14
5: update_grid_from_quote_str
at /home/tanmay/Desktop/projects/gnome/libipuz/_build/../libipuz/ipuz-acrostic.c:465:19
6: sync_quote_str_to_grid
at /home/tanmay/Desktop/projects/gnome/libipuz/_build/../libipuz/ipuz-acrostic.c:510:7
7: ipuz_acrostic_fix_quote_str
at /home/tanmay/Desktop/projects/gnome/libipuz/_build/../libipuz/ipuz-acrostic.c:568:5
8: ipuz_acrostic_real_fix_all
at /home/tanmay/Desktop/projects/gnome/libipuz/_build/../libipuz/ipuz-acrostic.c:314:11
9: ipuz_crossword_fix_all
at /home/tanmay/Desktop/projects/gnome/libipuz/_build/../libipuz/ipuz-crossword.c:2634:3
10: update_example
at ./_build/../src/edit-greeter-acrostic.c:285:3
11: quote_row_applied_cb
at ./_build/../src/edit-greeter-acrostic.c:319:3