Remove dotenv-mode package

Pruning packages that aren't strictly necessary.

core/cli/env.el

@@ -102,7 +102,7 @@ default, on Linux, this is '$SHELL -ic /usr/bin/env'. Variables in
            (goto-char (point-min))
            (insert
             (concat
-             "# -*- mode: dotenv -*-\n"
+             "# -*- mode: sh -*-\n"
              (format "# Generated from a %s shell environent\n" shell-file-name)
              "# ---------------------------------------------------------------------------\n"
              "# This file was auto-generated by `doom env'. It contains a list of environment\n"

core/packages.el

@@ -2,7 +2,6 @@
 ;;; core/packages.el
 
 ;; core.el
-(package! dotenv-mode)
 (package! auto-minor-mode)
 
 ;; core-ui.el