Bundled Themes: Add missing trailing / in HelpHub links.

HelpHub links without trailing slashes with anchors present result in an unnecessary redirect.

These were introduced with the `/` missing in [55476].

Props audrasjb.
See #57689, #57726.

git-svn-id: https://develop.svn.wordpress.org/trunk@55478 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-content/themes/twentytwentyone/readme.txt

@@ -33,7 +33,7 @@ No data is saved in the database or transferred.
 = 1.8 =
 * Released: March 28, 2023
 
-https://wordpress.org/documentation/article/twenty-twenty-one-changelog#Version_1.8
+https://wordpress.org/documentation/article/twenty-twenty-one-changelog/#Version_1.8
 
 = 1.7 =
 * Released: November 1, 2022

src/wp-content/themes/twentytwentythree/readme.txt

@@ -18,7 +18,7 @@ Whether you want to build a complex or incredibly simple website, you can do it
 = 1.1 =
 * Released: March 28, 2023
 
-https://wordpress.org/documentation/article/twenty-twenty-three-changelog#Version_1.1
+https://wordpress.org/documentation/article/twenty-twenty-three-changelog/#Version_1.1
 
 = 1.0 =
 * Released: November 1, 2022

src/wp-content/themes/twentytwentytwo/readme.txt

@@ -20,7 +20,7 @@ Whether you’re building a single-page website, a blog, a business website, or
 = 1.4 =
 * Released: March 28, 2023
 
-https://wordpress.org/documentation/article/twenty-twenty-two-changelog#Version_1.4
+https://wordpress.org/documentation/article/twenty-twenty-two-changelog/#Version_1.4
 
 = 1.3 =
 * Released: November 1, 2022