The TextRange property of a shape is its anchor position: if that's
adjusted, then also set the textbox's RES_ANCHOR to the new position.

Without this, e.g. shapes anchored in headers have their textboxes
anchored in the body text, CppunitTest_sw_ooxmlexport's testfdo78420 is
a reproducer.

Change-Id: I83ed09875c3f0360c581c331507ad2b9d05ffb3a