Typo

Co-Authored-By: mark-i-m <[email protected]>

Author: RalfJung

src/important-links.md

@@ -5,7 +5,7 @@ but we want them to work. For example, the stabilization guide link is often
 posted to tracking issues on GitHub, which might break later if the guide is
 changed.
 
-[Skip this file. Or read it; I'm book, not a cop.](https://imgur.com/gallery/mSHi8)
+[Skip this file. Or read it; I'm a book, not a cop.](https://imgur.com/gallery/mSHi8)
 
 [1](https://forge.rust-lang.org/stabilization-guide.html)
 [2](https://rust-lang.github.io/rustc-guide/stabilization_guide.html#documentation-prs)