Minor cleanups to theme-package error handling.

src/themes.lisp

@@ -22,17 +22,15 @@ any return value other than nil indicates the injection should be added."
     (list :head (injections-for :head)
           :body (injections-for :body))))
 
-(define-condition theme-does-not-exist-error (error)
+(define-condition theme-does-not-exist (error)
   ((theme :initarg :theme :reader theme))
   (:report (lambda (c stream)
-	     (format stream "THEME-DOES-NOT-EXIST-ERROR cannot find theme: '~A'" (theme c)))))
+             (format stream "Cannot find the theme: '~A'" (theme c)))))
 
 (defun theme-package (name)
-  "Find the package matching the theme NAME.  
-It will signal an error when it cannot find the package for the theme."
+  "Find the package matching the theme NAME or signal THEME-DOES-NOT-EXIST."
   (or (find-package (string-upcase (concatenate 'string "coleslaw.theme." name)))
-      (error 'theme-does-not-exist-error
-	     :theme name)))
+      (error 'theme-does-not-exist-error :theme name)))
 
 (defun theme-fn (name &optional (package (theme *config*)))
   "Find the symbol NAME inside PACKAGE which defaults to the theme package."