Revert "element: Un-escape code in inline source blocks"
This reverts commit 4056e11ddcb712e9e65cefdefed407ec197ffedf.
We shouldn't code escape inline source blocks, as escaping can be
inlined any time, at which point escape character is no longer treated
specially. E.g.,
src_c{a
,* 2}
may become
src_c{a ,* a}
where the comma is no longer an escape character.