Tilde not recognized as ending character in URL

[rbrewer]

If a URL ends in "~" the ~ will not be recognized as part of the URL, and therefore not highlighted for clickability. As far as I know, there is not reason why URLs can't end in ~, and it appears that the URLs in Kaiser Permanente's monthly newsletter always end that way.

To reproduce, just send yourself an email with a URL ending in "~". You will see that the blue underlining does not extend to the final ~.