Fix typo

Change-Id: I8d0eb79c1848714c637d05064b6aae5140843c20
Reviewed-on: https://gerrit.libreoffice.org/72707
Tested-by: Jenkins
Reviewed-by: Julien Nabet <serval2412@yahoo.fr>

editeng/source/items/bulitem.cxx

@@ -89,7 +89,7 @@ bool SvxBulletItem::operator==( const SfxPoolItem& rItem ) const
 {
     DBG_ASSERT(dynamic_cast< const SvxBulletItem* >(&rItem) !=  nullptr,"operator==Types not matching");
     const SvxBulletItem& rBullet = static_cast<const SvxBulletItem&>(rItem);
-    // Compare with ValidMask, otherwise no put possible in a AttrSet if the
+    // Compare with ValidMask, otherwise no put possible in an AttrSet if the
     // item differs only in terms of the ValidMask from an existing one.
     if( nStyle != rBullet.nStyle            ||
         nScale != rBullet.nScale            ||