zpao

# Replace Jekyll's handling of the Redcarpet code_block (which already adds
# support for highlighting, but needs support for the very non-standard
# "code fences with line highlights" extension).
# Since this is currently depending on Redcarpet to cooperate, we are going to
# be naive, and only allow line highlighting when a language is specified. If
# you don't want any syntax highlighting but want to highlight lines, then you
# need to specify text as your language (or it will break), like:
# ```text{4}

module Jekyll