docs: enhance README with information on semicolons and ASI in JavaScript

- Added a callout explaining Automatic Semicolon Insertion (ASI) and the rationale for omitting semicolons in the workshop.
- Provided a link to further reading on the topic for interested learners.

Author: kentcdodds

exercises/README.mdx

@@ -37,6 +37,17 @@ By the end of this workshop, you'll be able to:
 
 Let's build something solid! 🏗️
 
+<callout-info>
+	**Semicolons and ASI**: JavaScript has *Automatic Semicolon Insertion (ASI)*,
+	which means the runtime can insert semicolons when you omit them. In this
+	workshop, we leave semicolons out because our tooling handles the edge cases
+	(e.g. formatting and linting), and it's a style preference. It's also easier
+	to remember the few rules for when you **must** add a semicolon than to remember
+	all the rules for when you can safely omit them while still using semicolons.
+	If you're curious about the details and tradeoffs, see
+	[Semicolons in JavaScript: A preference](https://kentcdodds.com/blog/semicolons-in-javascript-a-preference).
+</callout-info>
+
 <callout-info>
 	**Code comments** are notes you write in your code that explain what it does.
 </callout-info>