mediawiki reader fails on tables when the line following a table caption starts with spaces

[LtdJorge]

Explain the problem.

A minimal example that works:

 {| class="wikitable"
 |+ Overview of basic table markup
! Key
 |-
 | Value
 |}

Same minimal example that doesn't work:

 {| class="wikitable"
 |+ Overview of basic table markup
 ! Key
 |-
 | Value
 |}

Notice how every line starts with a space. The amount of spaces is irrelevant, as long as it's more than 0. If you take the caption out, it works again:

 {| class="wikitable"
 ! Key
 |-
 | Value
 |}

I guess the issue is in

pandoc/src/Text/Pandoc/Readers/MediaWiki.hs

Lines 201 to 212 in 1e917dd

	table = do
	tableStart
	styles <- option [] $
	parseAttrs <* skipMany spaceChar <* optional (char '|')
	skipMany spaceChar
	optional $ template >> skipMany spaceChar
	optional blanklines
	let tableWidth = case lookup "width" styles of
	Just w -> fromMaybe 1.0 $ parseWidth w
	Nothing -> 1.0
	caption <- option mempty tableCaption
	optional rowsep

Or in

pandoc/src/Text/Pandoc/Readers/MediaWiki.hs

Lines 284 to 291 in 1e917dd

	tableCaption = try $ do
	optional rowsep
	guardColumnOne
	skipSpaces
	sym "|+"
	optional (try $ parseAttrs *> skipSpaces *> char '|' *> blanklines)
	trimInlines . mconcat <$>
	many (notFollowedBy (void cellsep <|> rowsep) *> inline)

rowsep looks good to me, but I don't know anything about Haskell.

Pandoc version?
This happens on "Try pandoc!" as well as on my local installation.
My local pandoc, on Gentoo Linux is:

pandoc 2.18
Compiled with pandoc-types 1.22.2, texmath 0.12.5.1, skylighting 0.12.3.1,
citeproc 0.7, ipynb 0.2, hslua 2.2.0
Scripting engine: Lua 5.4
User data directory: /home/jorge/.local/share/pandoc
Copyright (C) 2006-2022 John MacFarlane. Web:  https://pandoc.org
This is free software; see the source for copying conditions. There is no
warranty, not even for merchantability or fitness for a particular purpose.

[LtdJorge]

Thanks, John!