feat(eslint-plugin): [unbound-method] improve error message

packages/eslint-plugin/docs/rules/unbound-method.md

@@ -4,6 +4,8 @@ Warns when a method is used outside of a method call.
 
 Class functions don't preserve the class scope when passed as standalone variables.
 
+If you think it is intended, you can try to add `this: void` as the first function parameter or use arrow function instead.
+
 ## Rule Details
 
 Examples of **incorrect** code for this rule

packages/eslint-plugin/src/rules/unbound-method.ts

@@ -132,8 +132,8 @@ export default util.createRule<Options, MessageIds>({
       requiresTypeChecking: true,
     },
     messages: {
-      unbound:
-        'Avoid referencing unbound methods which may cause unintentional scoping of `this`.',
+      unbound: `Avoid referencing unbound methods which may cause unintentional scoping of \`this\`.
+If you think it is intended, you can try to add \`this: void\` as the first function parameter or use arrow function instead.`,
     },
     schema: [
       {