Reformat doctor output & add DOOMDIR check

- Will now warn you if both .doom.d and .config/doom exists.
- Include branch and last commit date in doctor/info, next to Doom
  version.
- Issues in Doom core are now indented.

core/autoload/debug.el

@@ -16,7 +16,7 @@ ready to be pasted in a bug report on github."
     (format
      (concat "- OS: %s (%s)\n"
              "- Emacs: %s (%s)\n"
-             "- Doom: %s (%s %s)\n"
+             "- Doom: %s (%s)\n"
              "- Graphic display: %s (daemon: %s)\n"
              "- System features: %s\n"
              "- Details:\n"
@@ -31,9 +31,7 @@ ready to be pasted in a bug report on github."
      system-type system-configuration
      emacs-version (format-time-string "%b %d, %Y" emacs-build-time)
      doom-version
-     (or (vc-git--symbolic-ref "core/core.el")
-         "n/a")
-     (or (vc-git-working-revision "core/core.el")
+     (or (string-trim (shell-command-to-string "git log -1 --format=\"%D %h %ci\""))
          "n/a")
      (display-graphic-p) (daemonp)
      (bound-and-true-p system-configuration-features)