X.H.UrgencyHook: Default for DzenUrgencyHook and UrgencyConfig

As the XMonad config is commonly customized by saying

    def { startupHook = ...
        , manageHook = ...
        , ...
        }

It seems consistent to allow the same for an individual hook config:

    let urgencyHook = def { suppressWhen = ...
                          , remindWhen = ...
                          }

CHANGES.md

@@ -29,6 +29,11 @@
     - Deprecated the module; use the new dynamic scratchpad
       functionality of `XMonad.Util.NamedScratchpad` instead.
 
+  * `XMonad.Hooks.UrgencyHook`
+
+    - Deprecated `urgencyConfig`; use `def` from the new `Default`
+      instance of `UrgencyConfig` instead.
+
 [on the website]: https://xmonad.org/configurations.html
 
 ### New Modules
@@ -199,6 +204,10 @@
     - Added an EDSL—particularly geared towards programs like terminals
       or Emacs—to spawn processes from XMonad in a compositional way.
 
+  * `XMonad.Hooks.UrgencyHook`
+
+    - Added a `Default` instance for `UrgencyConfig` and `DzenUrgencyHook`.
+
 ### Other changes
 
   * Migrated the sample build scripts from the deprecated `xmonad-testing` repo to

XMonad/Hooks/UrgencyHook.hs

@@ -197,11 +197,11 @@ import Foreign.C.Types (CLong)
 -- instead.
 withUrgencyHook :: (LayoutClass l Window, UrgencyHook h) =>
                    h -> XConfig l -> XConfig l
-withUrgencyHook hook = withUrgencyHookC hook urgencyConfig
+withUrgencyHook hook = withUrgencyHookC hook def
 
 -- | This lets you modify the defaults set in 'urgencyConfig'. An example:
 --
--- > withUrgencyHookC dzenUrgencyHook { ... } urgencyConfig { suppressWhen = Focused }
+-- > withUrgencyHookC dzenUrgencyHook { ... } def { suppressWhen = Focused }
 --
 -- (Don't type the @...@, you dolt.) See 'UrgencyConfig' for details on configuration.
 withUrgencyHookC :: (LayoutClass l Window, UrgencyHook h) =>
@@ -250,11 +250,16 @@ data RemindWhen = Dont                    -- ^ triggering once is enough
 minutes :: Rational -> Rational
 minutes secs = secs * 60
 
--- | The default 'UrgencyConfig'. suppressWhen = Visible, remindWhen = Dont.
+-- | The default 'UrgencyConfig': @urgencyConfig = 'def'@.
--- Use a variation of this in your config just as you use a variation of
--- 'def' for your xmonad definition.
 urgencyConfig :: UrgencyConfig
-urgencyConfig = UrgencyConfig { suppressWhen = Visible, remindWhen = Dont }
+urgencyConfig = def
+{-# DEPRECATED urgencyConfig "Use def insetad." #-}
+
+-- | The default 'UrgencyConfig': @suppressWhen = 'Visible', remindWhen = 'Dont'@.
+-- Use a variation of this in your config just as you would use any
+-- other instance of 'def'.
+instance Default UrgencyConfig where
+  def = UrgencyConfig { suppressWhen = Visible, remindWhen = Dont }
 
 -- | Focuses the most recently urgent window. Good for what ails ya -- I mean, your keybindings.
 -- Example keybinding:
@@ -510,7 +515,11 @@ instance UrgencyHook BorderUrgencyHook where
 -- Defaults to a duration of five seconds, and no extra args to dzen.
 -- See 'DzenUrgencyHook'.
 dzenUrgencyHook :: DzenUrgencyHook
-dzenUrgencyHook = DzenUrgencyHook { duration = seconds 5, args = [] }
+dzenUrgencyHook = def
+
+-- | @'def' = 'dzenUrgencyHook'@.
+instance Default DzenUrgencyHook where
+  def = DzenUrgencyHook { duration = seconds 5, args = [] }
 
 -- | Spawn a commandline thing, appending the window id to the prefix string
 -- you provide. (Make sure to add a space if you need it.) Do your crazy