Docx writer: Support bold and italic in "complex script."

Previously bold and italics didn't work properly in LTR
text.  This commit causes the w:bCs and w:iCs attributes
to be used, in addition to w:b and w:i, for bold and
italics respectively.

Closes #6911.

src/Text/Pandoc/Writers/Docx.hs

@@ -1272,9 +1272,13 @@ inlineToOpenXML' opts (Span (ident,classes,kvs) ils) = do
                      $ inlinesToOpenXML opts ils
   wrapBookmark ident contents
 inlineToOpenXML' opts (Strong lst) =
-  withTextProp (mknode "w:b" [] ()) $ inlinesToOpenXML opts lst
+  withTextProp (mknode "w:b" [] ()) $
+  withTextProp (mknode "w:bCs" [] ()) $ -- needed for LTR, #6911
+  inlinesToOpenXML opts lst
 inlineToOpenXML' opts (Emph lst) =
-  withTextProp (mknode "w:i" [] ()) $ inlinesToOpenXML opts lst
+  withTextProp (mknode "w:i" [] ()) $
+  withTextProp (mknode "w:iCs" [] ()) $  -- needed for LTR, #6911
+  inlinesToOpenXML opts lst
 inlineToOpenXML' opts (Underline lst) =
   withTextProp (mknode "w:u" [("w:val","single")] ()) $
     inlinesToOpenXML opts lst