fix the typo pointed out by jfe

lectures/git/slides.qmd

@@ -52,7 +52,7 @@ git config --global user.name "Your Name"
 git config --global user.email "youremail@yourdomain.com"
 ```
 
-## Hands-on Ssssion {background-color=var(--dark-bg-color)}
+## Hands-on Session {background-color=var(--dark-bg-color)}
 
 1. Configure the username and email adress in your local git client
 2. Initialize an empty Git repository