Document benefits from TypeScript annotation (#7423)

See https://www.typescriptlang.org/docs/handbook/jsdoc-supported-types.html

Co-authored-by: Marc G. <Mouvedia@users.noreply.github.com>
Co-authored-by: Richard Hallows <jeddy3@users.noreply.github.com>

docs/developer-guide/plugins.md

@@ -34,7 +34,8 @@ const meta = {
   url: "https://github.com/foo-org/stylelint-selector-no-foo/blob/main/README.md"
 };
 
-const ruleFunction = (primary, secondaryOptions) => {
+/** @type {import('stylelint').Rule} */
+const ruleFunction = (primary, secondaryOptions, context) => {
   return (root, result) => {
     const validOptions = validateOptions(result, ruleName, {
       actual: primary,
@@ -66,6 +67,9 @@ ruleFunction.meta = meta;
 export default createPlugin(ruleName, ruleFunction);
 ```
 
+> [!NOTE]
+> The [`@type` JSDoc annotation](https://www.typescriptlang.org/docs/handbook/jsdoc-supported-types.html#type) enables Typescript to autocomplete and type-check.
+
 The usage would be:
 
 ```json

docs/user-guide/configure.md

@@ -14,13 +14,17 @@ Stylelint expects a configuration object, and looks for one in a:
 ES module example:
 
 ```js
+/** @type {import('stylelint').Config} */
 export default {
   rules: {
     "block-no-empty": true
   }
 };
 ```
 
+> [!NOTE]
+> The `@type` JSDoc annotation enables Typescript to autocomplete and type-check.
+
 CommonJS example:
 
 ```js