Mediawiki writer: escape line-initial characters...

...that would otherwise be interpreted as list starts.

Closes #9700.

src/Text/Pandoc/Writers/MediaWiki.hs

@@ -117,9 +117,12 @@ blockToMediaWiki (Para inlines) = do
   tags <- asks useTags
   lev <- asks listLevel
   contents <- inlineListToMediaWiki inlines
+  let initEsc = if startsWithListMarker contents -- #9700
+                   then "\\"
+                   else ""
   return $ if tags
               then  "<p>" <> contents <> "</p>"
-              else contents <> if null lev then "\n" else ""
+              else initEsc <> contents <> if null lev then "\n" else ""
 
 blockToMediaWiki (LineBlock lns) =
   blockToMediaWiki $ linesToPara lns
@@ -1144,3 +1147,9 @@ highlightingLangs = Set.fromList [
   "yaml",
   "yaml+jinja",
   "zephir" ]
+
+startsWithListMarker :: Text -> Bool
+startsWithListMarker t =
+  case T.uncons t of
+    Nothing -> False
+    Just (c,_) -> c == '#' || c == ':' || c == ';' || c == '*'

test/command/9700.md

@@ -0,0 +1,14 @@
+```
+% pandoc -t mediawiki
+This is a normal sentence with a manual text footnote\*
+
+\* The footnote explains why it couldn't just be inside parentheses
+
+\#foobar \#foobar
+^D
+This is a normal sentence with a manual text footnote*
+
+\* The footnote explains why it couldn’t just be inside parentheses
+
+\#foobar #foobar
+```