Docx reader: Trim space inside the last inline.

We have to add one final mempty when we're combining in order to trim
inlines appropriately. (We need to use our own trimming routines here
due to the way that formatted inlines are smushed together when
converting from docx.)

Closes #5273

src/Text/Pandoc/Readers/Docx/Combine.hs

@@ -166,7 +166,8 @@ isAttrModifier (AttrModifier _ _) = True
 isAttrModifier _                  = False
 
 smushInlines :: [Inlines] -> Inlines
-smushInlines xs = foldl combineInlines mempty xs
+smushInlines xs = combineInlines xs' mempty
+  where xs' = foldl combineInlines mempty xs
 
 smushBlocks :: [Blocks] -> Blocks
 smushBlocks xs = foldl combineBlocks mempty xs