Update README.mdx (#370)

Looks like it was missing `with` for the following sentence to make sense:

"She's going to be hanging
around the rest of the crew..."

exercises/01.typescript/01.problem.props/README.mdx

@@ -4,7 +4,7 @@
 properly, so I want you to add type annotations.
 
 I'd also like you to meet Lily the Life Jacket! 🦺 She's going to be hanging
-around the rest of the crew to indicate wherever there's something that's
+around with the rest of the crew to indicate wherever there's something that's
 TypeScript-specific you need to do and to give you TypeScript-specific tips.
 You'll be working with Lily the Life Jacket a lot in this exercise.