Documentation: alias: rework notes into points

There are a number of caveats when using aliases.  Rather than
stuffing them all together in a paragraph, let's separate them out
into individual points to make it clearer what's going on.

Signed-off-by: Ian Wienand <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Documentation/config/alias.txt

@@ -21,8 +21,9 @@ If the alias expansion is prefixed with an exclamation point,
 it will be treated as a shell command.  For example, defining
 `alias.new = !gitk --all --not ORIG_HEAD`, the invocation
 `git new` is equivalent to running the shell command
-`gitk --all --not ORIG_HEAD`.  Note that shell commands will be
-executed from the top-level directory of a repository, which may
-not necessarily be the current directory.
-`GIT_PREFIX` is set as returned by running `git rev-parse --show-prefix`
-from the original current directory. See linkgit:git-rev-parse[1].
+`gitk --all --not ORIG_HEAD`.  Note:
++
+* Shell commands will be executed from the top-level directory of a
+  repository, which may not necessarily be the current directory.
+* `GIT_PREFIX` is set as returned by running `git rev-parse --show-prefix`
+  from the original current directory. See linkgit:git-rev-parse[1].