Pin git identity to dissimulo / connect+gitea@dustin-williams.com

Identity was previously deferred to ~/.gitconfig.user via the include
at the bottom of this file. Per the dotfiles owner, identity should
travel with the dotfiles regardless of host or local user — every
machine where this repo is deployed commits as dissimulo.

Per-machine bits (safe.directory, etc.) still belong in
~/.gitconfig.user, which the existing [include] at the bottom picks
up after this block.

git/gitconfig

@@ -1,5 +1,8 @@
 # set your user tokens as environment variables, such as ~/.secrets
 # See the README for examples.
+[user]
+	name = dissimulo
+	email = connect+gitea@dustin-williams.com
 [color]
   ui = true
 [color "branch"]