Allow using F12 as a shortcut

The system API says it’s reserved, but it doesn’t seem to be used for anything.

Sources/KeyboardShortcuts/KeyboardShortcuts.swift

@@ -48,7 +48,7 @@ public enum KeyboardShortcuts {
 
 	/**
 	Remove all handlers receiving keyboard shortcuts events.
-	
+
 	This can be used to reset the handlers before re-creating them to avoid having multiple handlers for the same shortcut.
 	*/
 	public static func removeAllHandlers() {

Sources/KeyboardShortcuts/NSMenuItem++.swift

@@ -1,7 +1,7 @@
 import Cocoa
 
 extension NSMenuItem {
-	private struct AssociatedKeys {
+	private enum AssociatedKeys {
 		static let observer = ObjectAssociation<NSObjectProtocol>()
 	}
 
@@ -68,7 +68,7 @@ extension NSMenuItem {
 
 	/**
 	Add a keyboard shortcut to a `NSMenuItem`.
-	
+
 	This method is only recommended for dynamic shortcuts. In general, it's preferred to create a static shortcut name and use `NSMenuItem.setShortcut(for:)` instead.
 
 	Pass in `nil` to clear the keyboard shortcut.

Sources/KeyboardShortcuts/RecorderCocoa.swift

@@ -83,18 +83,18 @@ extension KeyboardShortcuts {
 			self.placeholderString = "record_shortcut".localized
 			self.centersPlaceholder = true
 			self.alignment = .center
-			(self.cell as? NSSearchFieldCell)?.searchButtonCell = nil
+			(cell as? NSSearchFieldCell)?.searchButtonCell = nil
 
 			self.wantsLayer = true
 			self.translatesAutoresizingMaskIntoConstraints = false
-			self.setContentHuggingPriority(.defaultHigh, for: .vertical)
-			self.setContentHuggingPriority(.defaultHigh, for: .horizontal)
-			self.widthAnchor.constraint(greaterThanOrEqualToConstant: CGFloat(minimumWidth)).isActive = true
+			setContentHuggingPriority(.defaultHigh, for: .vertical)
+			setContentHuggingPriority(.defaultHigh, for: .horizontal)
+			widthAnchor.constraint(greaterThanOrEqualToConstant: CGFloat(minimumWidth)).isActive = true
 
 			// Hide the cancel button when not showing the shortcut so the placeholder text is properly centered. Must be last.
-			self.cancelButton = (self.cell as? NSSearchFieldCell)?.cancelButtonCell
+			self.cancelButton = (cell as? NSSearchFieldCell)?.cancelButtonCell
 
-			self.setStringValue(name: name)
+			setStringValue(name: name)
 
 			setUpEvents()
 		}

Sources/KeyboardShortcuts/Shortcut.swift

@@ -64,10 +64,18 @@ extension KeyboardShortcuts {
 
 extension KeyboardShortcuts.Shortcut {
 	/// System-defined keyboard shortcuts.
-	static var system: [Self] { CarbonKeyboardShortcuts.system }
+	static var system: [Self] {
+		CarbonKeyboardShortcuts.system
+	}
 
 	/// Check whether the keyboard shortcut is already taken by the system.
-	var isTakenBySystem: Bool { Self.system.contains(self) }
+	var isTakenBySystem: Bool {
+		guard self != KeyboardShortcuts.Shortcut(.f12, modifiers: []) else {
+			return false
+		}
+
+		return Self.system.contains(self)
+	}
 }
 
 extension KeyboardShortcuts.Shortcut {