Move custom error classes out of main file

src/easymde.ts

@@ -10,27 +10,13 @@ import { drawSelection, EditorView } from '@codemirror/view';
 import { tags } from '@lezer/highlight';
 import { marked } from 'marked';
 
+import { AlreadyConstructedError } from "./errors/already-constructed-error";
+import { NotConstructedError } from "./errors/not-constructed-error";
 import { InputOptions, Options } from './options';
 
 import './styles.scss';
 import { importDefaultToolbar, importToolbar } from '.';
 
-class NotConstructedError extends Error {
-    public constructor() {
-        super(
-            'EasyMDE is not initialized, run the "construct()" method to do so.',
-        );
-        this.name = 'NotConstructedError';
-    }
-}
-
-class AlreadyConstructedError extends Error {
-    public constructor() {
-        super('EasyMDE is already initialized.');
-        this.name = 'AlreadyConstructedError';
-    }
-}
-
 export class EasyMDE {
     private readonly element: HTMLTextAreaElement;
     #container?: HTMLDivElement;

src/errors/already-constructed-error.ts

@@ -0,0 +1,6 @@
+export class AlreadyConstructedError extends Error {
+    public constructor() {
+        super('EasyMDE is already initialized.');
+        this.name = 'AlreadyConstructedError';
+    }
+}

src/errors/not-constructed-error.ts

@@ -0,0 +1,8 @@
+export class NotConstructedError extends Error {
+    public constructor() {
+        super(
+            'EasyMDE is not initialized, run the "construct()" method to do so.',
+        );
+        this.name = 'NotConstructedError';
+    }
+}