Formatted all pages according to guidelines.

pages/common/git-checkout.md

@@ -1,15 +1,15 @@
 # git checkout
 
-> Checkout a branch or paths to the working tree
+> Checkout a branch or paths to the working tree.
 
-- Switch to another branch
+- Switch to another branch:
 
 `git checkout {{BRANCH-NAME}}`
 
-- Create and switch to a new branch
+- Create and switch to a new branch:
 
 `git checkout -b {{BRANCH-NAME}}`
 
-- Undo unstaged local modification
+- Undo unstaged local modification:
 
 `git checkout .`