[docs] Use %true and %false consistently

src/hb-common.cc

diff --git a/src/hb-common.cc b/src/hb-common.cc
index ddbcaa0..7615cc6 100644
--- a/src/hb-common.cc
+++ b/src/hb-common.cc
@@ -675,8 +675,8 @@
  * Tests the library version against a minimum value,
  * as three integer components.
  *
- * Return value: True if the library is equal to or greater than
- * the test value, false otherwise
+ * Return value: %true if the library is equal to or greater than
+ * the test value, %false otherwise
  *
  * Since: 0.9.30
  **/