fix: switchFile api to respect custom subtitle (#1672)

Author: bajrangCoder

src/lib/editorFile.js

@@ -944,6 +944,10 @@ export default class EditorFile {
 		}
 	}
 
+	get headerSubtitle() {
+		return this.#getTitle();
+	}
+
 	/**
 	 *
 	 * @param {FileAction} action

src/lib/editorManager.js

@@ -633,6 +633,7 @@ async function EditorManager($header, $body) {
 		if (activeFileId === id) return;
 
 		const file = manager.getFile(id);
+		if (!file) return;
 
 		manager.activeFile?.tab.classList.remove("active");
 
@@ -684,6 +685,7 @@ async function EditorManager($header, $body) {
 		}
 
 		$header.text = file.filename;
+		$header.subText = file.headerSubtitle || "";
 		manager.onupdate("switch-file");
 		events.emit("switch-file", file);
 	}