feat(preferences): shortcut for 'Display screen shortcuts'

'Show keyboard shortcuts' was unintuitive: app shortcuts only showed
Ctrl+Z

This makes the 'Access list of system / apps shortcuts' more prominent
by including it in the 'Current app' tab

It may be buggy on custom Android systems
which change this default shortcut, but should
work for the vast majority of systems

Fixes 18488

Author: david-allison

AnkiDroid/src/main/java/com/ichi2/anki/AnkiActivity.kt

@@ -704,6 +704,11 @@ open class AnkiActivity :
             ShortcutGroup(
                 listOf(
                     shortcut("Ctrl+Z", R.string.undo),
+                    // For 'Controls': to help user discover shortcuts in all screens
+                    // BUG: There is no way to access system shortcuts, so this may not be correct
+                    // This is copied from AOSP, which will be correct in most cases
+                    // https://cs.android.com/android/_/android/platform/frameworks/base/+/1cdfff555f4a21f71ccc978290e2e212e2f8b168:packages/SystemUI/src/com/android/systemui/keyboard/shortcut/data/source/SystemShortcutsSource.kt;l=162-166;bpv=1;bpt=0;drc=697cd49fb770afa8480d4c187b30553645b5879c
+                    shortcut("Meta+/", R.string.shortcut_label_show_shortcuts_for_app),
                 ),
                 R.string.pref_cat_general,
             ).toShortcutGroup(this)

AnkiDroid/src/main/java/com/ichi2/anki/android/input/Shortcut.kt

@@ -51,14 +51,15 @@ data class Shortcut(
     /**
      * Maps a modifier string to its corresponding KeyEvent meta flag.
      *
-     * @param modifier The modifier string (e.g., "Ctrl", "Alt", "Shift").
+     * @param modifier The modifier string (e.g., "Ctrl", "Alt", "Shift", "Meta").
      * @return The corresponding KeyEvent meta flag.
      */
     private fun getModifier(modifier: String): Int =
         when (modifier) {
             "Ctrl" -> KeyEvent.META_CTRL_ON
             "Alt" -> KeyEvent.META_ALT_ON
             "Shift" -> KeyEvent.META_SHIFT_ON
+            "Meta" -> KeyEvent.META_META_ON
 
             else -> 0
         }

AnkiDroid/src/main/res/values/02-strings.xml

@@ -407,5 +407,7 @@ opening the system text to speech settings fails">Failed to open text to speech
     <string name="missing_user_action_dialog_message" comment="%s is the user action number">User action %s is not set in this notetype. Please configure it</string>
 
     <string name="directory_inaccessible_info">Learn more about how to restore access here %s or go to settings to update collection folder.</string>
+
+    <string name="shortcut_label_show_shortcuts_for_app">Display screen shortcuts</string>
 </resources>