LaTeX writer: put a strut after a line break (\\).

This ensures that we have proper spacing before the next
line (which might e.g. be a table bottom border).
This gives better results in cases like test/command/7272.md.

src/Text/Pandoc/Writers/LaTeX.hs

@@ -919,7 +919,7 @@ inlineToLaTeX il@(RawInline f str) = do
 inlineToLaTeX LineBreak = do
   emptyLine <- gets stEmptyLine
   setEmptyLine True
-  return $ (if emptyLine then "\\strut " else "") <> "\\\\" <> cr
+  return $ (if emptyLine then "\\strut " else "") <> "\\\\ \\strut" <> cr
 inlineToLaTeX SoftBreak = do
   wrapText <- gets (writerWrapText . stOptions)
   case wrapText of