.gitconfig: Delete unnecessary comments
.gitconfig: Sort aliases
.gitconfig: Shorten branch alias to b
.gitconfig: Add a alias bd which means "branch -d"
.gitconfig: Add a alias d which means "diff"
.gitconfig: Shorten fetch alias to f
.gitconfig: Shorten log alias to l
.gitconfig: Duplicate log-s alias to lg
.gitconfig: Shorten sh alias to s
.gitconfig: Add a alias sa which means "stash apply"
.gitconfig: Add a alias sd which means "stash drop"
.gitconfig: Add a alias sl which means "stash list"
.gitconfig: Add a alias sp which means "stash pop"
.gitconfig: Add a alias ss which means "stash save"
.gitconfig: Add a alias t which means "tag"
.gitconfig: Add a alias cp which means "cherry-pick"
.gitconfig: Add s[n] aliases which mean "show HEAD~n"
.gitconfig: Set push.default to current
.gitconfig: Add option about core.pager
.gitconfig: Simplify color.ui option