patch 9.0.1815: pango_coverage_unref() deprecated in pango > 1.51

Problem:  pango_coverage_unref() deprecated in pango > 1.51
Solution: use g_object_unref() instead

closes: #12942

Free PangoCoverage with g_object_unref for Pango >= 1.52

pango_coverage_unref was declared deprecated in Pango 1.52.0 in favor of
g_object_unref.  Adjust the call when building against a new enough
Pango to avoid the deprecation warning.

Signed-off-by: James McCoy <jamessan@jamessan.com>
Co-authored-by: James McCoy <jamessan@jamessan.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/gui_gtk_x11.c b/src/gui_gtk_x11.c
index 1f8b2eb..3f0cf8c 100644
--- a/src/gui_gtk_x11.c
+++ b/src/gui_gtk_x11.c
@@ -4845,7 +4845,11 @@
 	{
 	    uc = (cjk_langs[i][0] == 'k') ? 0xAC00 : 0x4E00;
 	    is_cjk = (pango_coverage_get(coverage, uc) == PANGO_COVERAGE_EXACT);
+#if PANGO_VERSION_CHECK(1, 52, 0)
+	    g_object_unref(coverage);
+#else
 	    pango_coverage_unref(coverage);
+#endif
 	}
     }