doc: config: fix list continuation in alias section

ac1f12a9 (alias: support non-alphanumeric names via subsection syntax,
2026-02-18) did not use list continuation for this code block[1] which
means that the block ends after it. In turn the paragraph starting with
`git last` goes to the outer block and the next paragraphs are not
continued properly.

We can simply add list continuation right before and after the code
block. Let’s of course do that, but let’s also change to use a non-
indented code block (----) in line with the preceding configuration
example.

Also use `$ #` for the comment to be consistent with
the terminal prompt.

† 1: From https://lore.kernel.org/git/xmqqqzqqrk2h.fsf@gitster.g/

Signed-off-by: Kristoffer Haugsbakk <code@khaugsbakk.name>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/config/alias.adoc

@@ -30,11 +30,13 @@ Examples:
 ----
 +
 With a Git alias defined, e.g.,
-
-    $ git config --global alias.last "cat-file commit HEAD"
-    # Which is equivalent to
-    $ git config --global alias.last.command "cat-file commit HEAD"
-
++
+----
+$ git config --global alias.last "cat-file commit HEAD"
+$ # Which is equivalent to
+$ git config --global alias.last.command "cat-file commit HEAD"
+----
++
 `git last` is equivalent to `git cat-file commit HEAD`. To avoid
 confusion and troubles with script usage, aliases that
 hide existing Git commands are ignored except for deprecated