Improve Public API (#339)

### Description

Makes some slight adjustments to the public API.
- Adds new, optional, `controllerDidAppear/Disappear` methods to text
coordinators.
- Makes the textView and scrollView properties on the text view
controller have `public` getters.

### Related Issues

Related to issues brought up on Discord.

### Checklist

- [x] I read and understood the [contributing
guide](https://github.com/CodeEditApp/CodeEdit/blob/main/CONTRIBUTING.md)
as well as the [code of
conduct](https://github.com/CodeEditApp/CodeEdit/blob/main/CODE_OF_CONDUCT.md)
- [x] The issues this PR addresses are related to each other
- [x] My changes generate no new warnings
- [x] My code builds and runs on my machine
- [x] My changes are all related to the related issue above
- [x] I documented my code

### Screenshots

No UI Changes

Author: thecoolwinter

Sources/CodeEditSourceEditor/Controller/TextViewController.swift

@@ -24,8 +24,8 @@ public class TextViewController: NSViewController {
 
     weak var findViewController: FindViewController?
 
-    var scrollView: NSScrollView!
-    var textView: TextView!
+    internal(set) public var scrollView: NSScrollView!
+    internal(set) public var textView: TextView!
     var gutterView: GutterView!
     var minimapView: MinimapView!
 
@@ -256,6 +256,16 @@ public class TextViewController: NSViewController {
         minimapView.layout()
     }
 
+    override public func viewDidAppear() {
+        super.viewDidAppear()
+        textCoordinators.forEach { $0.val?.controllerDidAppear(controller: self) }
+    }
+
+    override public func viewDidDisappear() {
+        super.viewDidDisappear()
+        textCoordinators.forEach { $0.val?.controllerDidDisappear(controller: self) }
+    }
+
     deinit {
         if let highlighter {
             textView.removeStorageDelegate(highlighter)

Sources/CodeEditSourceEditor/TextViewCoordinator/TextViewCoordinator.swift

@@ -26,6 +26,14 @@ public protocol TextViewCoordinator: AnyObject {
     ///                         dereferenced when ``TextViewCoordinator/destroy()-9nzfl`` is called.
     func prepareCoordinator(controller: TextViewController)
 
+    /// Called when the controller's `viewDidAppear` method is called by AppKit.
+    /// - Parameter controller: The text view controller that did appear.
+    func controllerDidAppear(controller: TextViewController)
+
+    /// Called when the controller's `viewDidDisappear` method is called by AppKit.
+    /// - Parameter controller: The text view controller that did disappear.
+    func controllerDidDisappear(controller: TextViewController)
+
     /// Called when the text view's text changed.
     /// - Parameter controller: The text controller.
     func textViewDidChangeText(controller: TextViewController)
@@ -40,6 +48,8 @@ public protocol TextViewCoordinator: AnyObject {
 
 /// Default implementations
 public extension TextViewCoordinator {
+    func controllerDidAppear(controller: TextViewController) { }
+    func controllerDidDisappear(controller: TextViewController) { }
     func textViewDidChangeText(controller: TextViewController) { }
     func textViewDidChangeSelection(controller: TextViewController, newPositions: [CursorPosition]) { }
     func destroy() { }