fix: typo

Author: Dup4

install/debian.md

@@ -60,7 +60,7 @@ $ echo \
 
 # 官方源
 # $ echo \
-#   "deb [arch=amd64 signed-by=/usr/share/keyrings/docker-archive-keyring.gpg] https://https://download.docker.com/linux/debian \
+#   "deb [arch=amd64 signed-by=/usr/share/keyrings/docker-archive-keyring.gpg] https://download.docker.com/linux/debian \
 #   $(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null
 
 ```