Revert "work around https://bugreports.qt.io/browse/QTBUG-54755"

This reverts commit 0bd79abe11.

aqt/main.py

@@ -647,13 +647,6 @@ title="%s" %s>%s</button>''' % (
             self.onStats()
         elif key == "y":
             self.onSync()
-        # temp accelerators to work around bug
-        elif key == "/":
-            self.onStudyDeck()
-        elif key == "f":
-            self.onCram()
-        elif evt.matches(QKeySequence.Undo):
-            self.onUndo()
 
     # App exit
     ##########################################################################

designer/main.ui

@@ -145,6 +145,9 @@
    <property name="text">
     <string>&amp;Undo</string>
    </property>
+   <property name="shortcut">
+    <string>Ctrl+Z</string>
+   </property>
   </action>
   <action name="actionCheckMediaDatabase">
    <property name="text">
@@ -213,6 +216,9 @@
    <property name="text">
     <string>Study Deck...</string>
    </property>
+   <property name="shortcut">
+    <string>/</string>
+   </property>
   </action>
   <action name="actionEmptyCards">
    <property name="text">
@@ -223,6 +229,9 @@
    <property name="text">
     <string>Create Filtered Deck...</string>
    </property>
+   <property name="shortcut">
+    <string>F</string>
+   </property>
   </action>
   <action name="actionNoteTypes">
    <property name="text">