Remove obsolete references to Gitter

No one uses it

editions/tw5.com/tiddlers/about/Developers.tid

@@ -20,5 +20,3 @@ There are several resources for developers to learn more about TiddlyWiki and to
 * The older ~TiddlyWikiDev Google Group is now closed in favour of [[Talk TiddlyWiki|https://talk.tiddlywiki.org/]] and [[GitHub Discussions|https://github.com/TiddlyWiki/TiddlyWiki5/discussions]] 
 ** It remains a useful archive: https://groups.google.com/group/TiddlyWikiDev
 *** An enhanced group search facility is available on [[mail-archive.com|https://www.mail-archive.com/tiddlywikidev@googlegroups.com/]]
-
-* Chat at https://gitter.im/TiddlyWiki/public (development room coming soon)

editions/tw5.com/tiddlers/community/Forums.tid

@@ -27,7 +27,6 @@ For the convenience of existing users, we also continue to operate the original
 ! Other Forums
 
 * [[TiddlyWiki Subreddit|https://www.reddit.com/r/TiddlyWiki5/]]
-* Chat with Gitter at https://gitter.im/TiddlyWiki/public !
 * Chat on Discord at https://discord.gg/HFFZVQ8
 
 !! Documentation

editions/tw5.com/tiddlers/community/TiddlyWiki on the Web.tid

@@ -1,7 +1,7 @@
 color: #808
 created: 20241009150445080
 icon: $:/core/images/link
-list: TalkTiddlyWiki [[TiddlyWiki on YouTube]] [[TiddlyWiki on Reddit]] [[TiddlyWiki on Discord]] [[TiddlyWiki on GitHub]] [[TiddlyWiki on Mastodon]] [[TiddlyWiki on Gitter]] [[TiddlyWiki on Open Collective]]
+list: TalkTiddlyWiki [[TiddlyWiki on YouTube]] [[TiddlyWiki on Reddit]] [[TiddlyWiki on Discord]] [[TiddlyWiki on GitHub]] [[TiddlyWiki on Mastodon]] [[TiddlyWiki on Open Collective]]
 modified: 20241115170824144
 tags: Welcome
 title: TiddlyWiki on the Web

editions/tw5.com/tiddlers/community/links/TiddlyWiki on Gitter.tid

@@ -1,7 +0,0 @@
-title: TiddlyWiki on Gitter
-caption: Gitter
-tags: [[TiddlyWiki on the Web]]
-url: https://gitter.im/TiddlyWiki/public
-icon: $:/core/images/gitter
-background-color: #753a88
-text-color: #fff