Re-add display: inline-block, but only to print CSS.

See jgm/pandoc#7248 for an explanation of why this was removed
from the regular CSS, and see jgm/pandoc#9520 for an explanation
of the problems this causes in printed output.

skylighting-format-blaze-html/src/Skylighting/Format/HTML.hs

@@ -205,7 +205,7 @@ styleToCss f = unlines $
  , "}"
  , "@media print {"
  , "pre > code.sourceCode { white-space: pre-wrap; }"
- , "pre > code.sourceCode > span { text-indent: -5em; padding-left: 5em; }"
+ , "pre > code.sourceCode > span { display: inline-block; text-indent: -5em; padding-left: 5em; }"
  , "}"
  ]
  linkspec = [ "@media screen {"