tree: remove defcustom :group keywords

esv.el

@@ -41,28 +41,23 @@
 
 (defcustom esv-close-existing-buffers nil
   "Whether to close an existing `esv' buffer if one already exists."
-  :type 'boolean
-  :group 'esv)
+  :type 'boolean)
 
 (defcustom esv-columns 72
   "Length of each line output by `esv'."
-  :type 'natnum
-  :group 'esv)
+  :type 'natnum)
 
 (defcustom esv-mode-hook nil
   "Hook run after entering `esv-mode'."
-  :type 'hook
-  :group 'esv)
+  :type 'hook)
 
 (defcustom esv-process "esv"
   "Name of the process created by `esv'."
-  :type 'string
-  :group 'esv)
+  :type 'string)
 
 (defcustom esv-program "esv"
   "Path to or name of the program started by `esv'."
-  :type 'string
-  :group 'esv)
+  :type 'string)
 
 (defvar esv-arguments '()
   "List of additional arguments passed to `esv-program'.")

phobos.el

@@ -43,19 +43,15 @@
 
 (defcustom phobos-browser "xdg-open"
   "Web browser to use when opening documentation with `phobos'."
-  :group 'phobos
   :type 'string)
 (defcustom phobos-root "https://dlang.org/library"
   "Root URL to use when viewing documentation with `phobos'."
-  :group 'phobos
   :type 'string)
 (defcustom phobos-dpldocs-domain "dpldocs.info"
   "Root domain to use when viewing documentation on dub packages with `dub-doc'."
-  :group 'phobos
   :type 'string)
 (defcustom phobos-registry-root "https://code.dlang.org"
   "Root URL of the D package registry used with `describe-dub-package'."
-  :group 'phobos
   :type 'string)
 
 (defun phobos--visit (&rest format-args)