[docs] Add generic props usage examples

docs/src/pages/components/typography/typography.md

@@ -98,3 +98,31 @@ A few key factors to follow for an accessible typography:
 - **Color**. Provide enough contrast between text and its background, check out the minimum recommended [WCAG 2.0 color contrast ratio](https://www.w3.org/TR/UNDERSTANDING-WCAG20/visual-audio-contrast-contrast.html) (4.5:1).
 - **Font size**. Use [relative units (rem)](/customization/typography/#font-size) to accommodate the user's settings.
 - **Heading hierarchy**. [Don't skip](https://www.w3.org/WAI/tutorials/page-structure/headings/) heading levels. In order to solve this problem, you need to [separate the semantics from the style](#changing-the-semantic-element).
+
+## `TypographyProps` usage with TypeScript
+
+Typography supports changing of the root node with `component` prop. To be able to use `TypographyProps` on their own (for example to type custom component) with the `component` prop, `TypographyProps` should be used with type arguments. Otherwise `component` prop will not be present in `TypographyProps`.
+For example 
+```ts
+const CustomComponent: React.FC<TypographyProps<'a', { component: 'a' }>> = 
+  (props) => (/* ... */);
+```
+Now the `CustomComponent` can be used with a `component` prop which should be set to `'a'`. In addition, the `CustomComponent` will have all props of `<a>` HTML element.
+
+It is possible to have generic `CustomComponent` which will accept any React component, custom and HTML elements. 
+```ts
+function GenericCustomComponent<C extends React.ElementType> (props: TypographyProps<C, {component?: C}>) { 
+  /* ... */ 
+}
+```
+Now if the `GenericCustomComponent` will be used with a `component` prop provided, it should also have any props required by the provided component.
+```ts
+const ThirdPartyComponent: FC<{prop1: string}> = 
+  (props) => (<div/>);
+// ...
+<GenericCustomComponent 
+  component={ThirdPartyComponent} 
+  prop1='some value'
+/>
+```
+The `prop1` became required for the `GenericCustomComponent` as the `ThirdPartyComponent` has it as a requirement.