Fix typo

Change-Id: Ib1af986d52bbc4ea7e2ee7dc5964da81e6508265
Reviewed-on: https://gerrit.libreoffice.org/73137
Tested-by: Jenkins
Reviewed-by: Jens Carl <j.carl43@gmx.de>

filter/source/msfilter/eschesdo.cxx

@@ -972,7 +972,7 @@ sal_uInt32 EscherEx::QueryTextID( const Reference< XShape >&, sal_uInt32 )
     return 0;
 }
 
-// add an dummy rectangle shape into the escher stream
+// add a dummy rectangle shape into the escher stream
 sal_uInt32 EscherEx::AddDummyShape()
 {
     OpenContainer( ESCHER_SpContainer );