Also allow . to be a delimiter for a link.

R/link-elements.R

@@ -99,7 +99,7 @@ markup_href <- function(x) {
 common_regex <- function(which) {
   x <- c(
     # usage of double negation will make it work
-    md_url = "(?<!\\{\\.href\\s)(\\[[^\\[\\]]+\\])(\\(https[^,\\s]+\\)(?![^\\s,\\:;$\\)]))",
+    md_url = "(?<!\\{\\.href\\s)(\\[[^\\[\\]]+\\])(\\(https[^,\\s]+\\)(?![^\\s,\\:;\\.$\\)]))",
     gh_issue = "([[:alpha:]][[:graph:]]+/[^#\\s]+)#(\\d+)"
   )
   unname(x[which])