Add canned filter for recent system tiddlers

Useful when you need to establish the titles of tiddlers being used for
state storage.

core/language/en-GB/Filters.multids

@@ -1,6 +1,7 @@
 title: $:/language/Filters/
 
 AllTiddlers: All tiddlers except system tiddlers
+RecentSystemTiddlers: Recently modified tiddlers, including system tiddlers
 RecentTiddlers: Recently modified tiddlers
 AllTags: All tags except system tags
 Missing: Missing tiddlers

core/ui/Filters/RecentSystemTiddlers.tid

@@ -0,0 +1,5 @@
+title: $:/core/Filters/RecentSystemTiddlers
+tags: $:/tags/Filter
+filter: [has[modified]!sort[modified]limit[50]]
+description: {{$:/language/Filters/RecentSystemTiddlers}}
+

core/ui/Filters/RecentTiddlers.tid

@@ -1,5 +1,5 @@
 title: $:/core/Filters/RecentTiddlers
 tags: $:/tags/Filter
-filter: [!is[system]has[modified]!sort[modified]]
+filter: [!is[system]has[modified]!sort[modified]limit[50]]
 description: {{$:/language/Filters/RecentTiddlers}}