Only one line in a multi-line string can be escaped; multiple should be possible

[abstrctn]

Ever backslash-escaped line in the following example should be removed in the final output:

key: value
\:ignore
\:skip
\:endskip
:end

However, only the first backslash is getting removed. The regexp that we are using to remove leading backslashes does not have the g or m flags, both of which are necessary to correctly remove every backslash.