docs: modify examples for explicit-module-boundary-types (#7404)

* docs : modify examples for explicit-module-boundary-types

* docs : update examples for explicit-module-boundary-types

* docs: fix atx-style

* docs: update code based on the request

* docs: fix typo

* docs: change case 3 to case 1

packages/eslint-plugin/docs/rules/explicit-module-boundary-types.md

@@ -22,11 +22,6 @@ export function test() {
   return;
 }
 
-// Should indicate that a number is returned
-export default function () {
-  return 1;
-}
-
 // Should indicate that a string is returned
 export var arrowFn = () => 'test';
 
@@ -45,29 +40,29 @@ export class Test {
 ### ✅ Correct
 
 ```ts
-// Function is not exported
-function test() {
+// A function with no return value (void)
+export function test(): void {
   return;
 }
 
-// A return value of type number
-export var fn = function (): number {
-  return 1;
-};
-
 // A return value of type string
 export var arrowFn = (): string => 'test';
 
 // All arguments should be typed
 export var arrowFn = (arg: string): string => `test ${arg}`;
 export var arrowFn = (arg: unknown): string => `test ${arg}`;
 
-// Class is not exported
-class Test {
-  method() {
+export class Test {
+  // A class method with no return value (void)
+  method(): void {
     return;
   }
 }
+
+// The function does not apply because it is not an exported function.
+function test() {
+  return;
+}
 ```
 
 ## Options