Fix default global keyboard shortcuts for Mac

Fixes #3610

core/wiki/config/shortcuts/shortcuts-mac.multids

@@ -3,3 +3,6 @@ title: $:/config/shortcuts-mac/
 bold: meta-B
 italic: meta-I
 underline: meta-U
+new-image: ctrl-I
+new-journal: ctrl-J
+new-tiddler: ctrl-N

core/wiki/config/shortcuts/shortcuts-not-mac.multids

@@ -3,3 +3,6 @@ title: $:/config/shortcuts-not-mac/
 bold: ctrl-B
 italic: ctrl-I
 underline: ctrl-U
+new-image: alt-I
+new-journal: alt-J
+new-tiddler: alt-N

core/wiki/config/shortcuts/shortcuts.multids

@@ -14,9 +14,6 @@ list-bullet: ctrl-shift-L
 list-number: ctrl-shift-N
 mono-block: ctrl-shift-M
 mono-line: ctrl-M
-new-image: alt-I
-new-journal: alt-J
-new-tiddler: alt-N
 picture: ctrl-shift-I
 preview: alt-P
 quote: ctrl-Q

editions/prerelease/tiddlers/Release 5.1.18.tid

@@ -13,9 +13,9 @@ type: text/vnd.tiddlywiki
 
 This version introduces new infrastructure to handle global keyboard shortcuts. The core ships with the following shortcuts:
 
-* <kbd>alt-I</kbd> - New image
-* <kbd>alt-J</kbd> - New journal
-* <kbd>alt-N</kbd> - New tiddler
+* <kbd>alt-I</kbd> (or <kbd>ctrl-I</kbd> on Mac) - New image
+* <kbd>alt-J</kbd> (or <kbd>ctrl-J</kbd> on Mac) - New journal
+* <kbd>alt-N</kbd> (or <kbd>ctrl-N</kbd> on Mac) - New tiddler
 
 See [[How to create keyboard shortcuts]]