Exclude `?`, `!`, and `)` from last character of URL

Now the final character in each of these example strings is no longer
considered part of the URL:
  * Have you seen http://example.com?
  * Look at http://example.com!
  * (see http://example.com)

src/static/js/pad_utils.js

@@ -63,7 +63,7 @@ const urlRegex = (() => {
   const urlChar = `[-:@_.,~%+/?=&#!;()$${wordCharRegex.source.slice(1, -1)}]`;
   // Matches a single character that should not be considered part of the URL if it is the last
   // character that matches urlChar.
-  const postUrlPunct = '[:.,;]';
+  const postUrlPunct = '[:.,;?!)]';
   // Schemes that must be followed by ://
   const withAuth = `(?:${[
     '(?:x-)?man',

tests/frontend/specs/urls_become_clickable.js

@@ -44,7 +44,7 @@ describe('urls', function () {
   });
 
   describe('punctuation after URL is ignored', function () {
-    for (const char of ':.,;]') {
+    for (const char of ':.,;?!)]') {
       const want = 'https://etherpad.org';
       const input = want + char;
       it(input, async function () {