docs: improve rule docs

Author: Rel1cx

packages/eslint-plugin-jsx/src/rules/no-leaked-conditional-rendering.md

@@ -153,10 +153,6 @@ function Component({ elements }) {
 }
 ```
 
-## When Not To Use It
-
-If you are working in a typed-codebase which encourages you to always use boolean conditions, this rule can be disabled.
-
 ## Further Reading
 
 - [react.dev: Conditional Rendering](https://react.dev/learn/conditional-rendering)

packages/eslint-plugin-react/src/rules/no-missing-button-type.md

@@ -28,6 +28,6 @@ The `button` element's `type` attribute must be specified explicitly. The defaul
 <button type="button">Click me</button>;
 ```
 
-## When Not To Use It
+## Further Reading
 
-If you use only "submit" buttons, you can disable this rule
+- [MDN: button - notes](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/button#notes)

packages/eslint-plugin-react/src/rules/no-missing-iframe-sandbox.md

@@ -57,10 +57,6 @@ const Component = () => {
 };
 ```
 
-## When not to use
-
-If you don't want to enforce sandbox attribute on iframe elements.
-
 ## Further Reading
 
--[MDN: Element/iframe#attr-sandbox](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/iframe#attr-sandbox)
+-[MDN: iframe - sandbox](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/iframe#attributes)

packages/eslint-plugin-react/src/rules/no-unsafe-iframe-sandbox.md

@@ -60,6 +60,6 @@ const Component = () => {
 };
 ```
 
-## When not to use
+## Further Reading
 
-If you don't want to enforce sandbox attribute on iframe elements.
+- [MDN: iframe - sandbox](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/iframe#attributes)

website/styles/base.scss

@@ -59,6 +59,15 @@ html[lang] {
   font-family: var(--font-family-ui-mono);
 }
 
+h1,
+h2,
+h3,
+h4,
+h5,
+h6 {
+  font-family: var(--font-family-ui);
+}
+
 h1,
 h2,
 h3 {