Escaping around markdown links

[jimhester]

The % needs to be escaped once for the Rd, but the \ should only occur once, not twice in the link text.

Current behavior

#' [magrittr::\%>\%]

\link[magrittr:\\%>\\%]{magrittr::\%>\%}

[hadley]

Given that ` escapes %, I think the input should be [magrittr::%>%]