when discarding a trailing paren from an auto-linked URL, we have to …

…re-check the last character to exclude punctuation (http://meta.stackoverflow.com/q/179990)

Markdown.Converter.js

@@ -1231,7 +1231,12 @@ else
             text = text.replace(/\\([`*_{}\[\]()>#+-.!])/g, escapeCharacters_callback);
             return text;
         }
-
+
+        var charInsideUrl = "[-A-Z0-9+&@#/%?=~_|[\\]()!:,.;]",
+            charEndingUrl = "[-A-Z0-9+&@#/%=~_|[\\])]",
+            autoLinkRegex = new RegExp("(=\"|<)?\\b(https?|ftp)(://" + charInsideUrl + "*" + charEndingUrl + ")(?=$|\\W)", "gi"),
+            endCharRegex = new RegExp(charEndingUrl, "i");
+
         function handleTrailingParens(wholeMatch, lookbehind, protocol, link) {
             if (lookbehind)
                 return wholeMatch;
@@ -1258,10 +1263,16 @@ else
                     return "";
                 });
             }
-
+            if (tail) {
+                var lastChar = link.charAt(link.length - 1);
+                if (!endCharRegex.test(lastChar)) {
+                    tail = lastChar + tail;
+                    link = link.substr(0, link.length - 1);
+                }
+            }
             return "<" + protocol + link + ">" + tail;
         }
-
+        
         function _DoAutoLinks(text) {
 
             // note that at this point, all other URL in the text are already hyperlinked as <a href=""></a>
@@ -1271,7 +1282,7 @@ else
             // must be preceded by a non-word character (and not by =" or <) and followed by non-word/EOF character
             // simulating the lookbehind in a consuming way is okay here, since a URL can neither and with a " nor
             // with a <, so there is no risk of overlapping matches.
-            text = text.replace(/(="|<)?\b(https?|ftp)(:\/\/[-A-Z0-9+&@#\/%?=~_|\[\]\(\)!:,\.;]*[-A-Z0-9+&@#\/%=~_|\[\])])(?=$|\W)/gi, handleTrailingParens);
+            text = text.replace(autoLinkRegex, handleTrailingParens);
 
             //  autolink anything like <http://example.com>