explicit way to express that those are different choice and not just one big file to create

Signed-off-by: gissehel <public-devgit-dantus@gissehel.org>

docs/installation/debian.md

@@ -63,10 +63,18 @@ from the new repository:
 
      The possible entries are:
 
+     - On Debian Wheezy
+
             # Debian Wheezy
             deb https://apt.dockerproject.org/repo debian-wheezy main
+
+    - On Debian Jessie
+
             # Debian Jessie
             deb https://apt.dockerproject.org/repo debian-jessie main
+
+    - On Debian Stretch/Sid
+
             # Debian Stretch/Sid
             deb https://apt.dockerproject.org/repo debian-stretch main
 

docs/installation/ubuntulinux.md

@@ -67,12 +67,23 @@ packages from the new repository:
 
     The possible entries are:
 
+    - On Ubuntu Precise 12.04 (LTS)
+
             # Ubuntu Precise 12.04 (LTS)
             deb https://apt.dockerproject.org/repo ubuntu-precise main
+
+    - On Ubuntu Trusty 14.04 (LTS)
+
             # Ubuntu Trusty 14.04 (LTS)
             deb https://apt.dockerproject.org/repo ubuntu-trusty main
+
+    - On Ubuntu Vivid 15.04
+
             # Ubuntu Vivid 15.04
             deb https://apt.dockerproject.org/repo ubuntu-vivid main
+
+    - Ubuntu Wily 15.10
+
             # Ubuntu Wily 15.10
             deb https://apt.dockerproject.org/repo ubuntu-wily main