Merge #379

379: make that link hyper r=spookyvision a=spookyvision

there's a link to the stable website, and now it's clickable!

Co-authored-by: Anatol Ulrich <anatol.ulrich@ferrous-systems.com>
Co-authored-by: Anatol Ulrich <45840+spookyvision@users.noreply.github.com>

book/src/introduction.md

@@ -4,7 +4,7 @@
 
 > **NOTE** this hosted version of the `defmt` book corresponds to the *unreleased* `defmt` v0.2.0,
 > which is currently only available as a git dependency. If you are looking for `defmt` v0.1.x's
-> documentation head to https://defmt.ferrous-systems.com
+> documentation head to <https://defmt.ferrous-systems.com>.
 
 ## Features