Add CPP Options for Stylish Haskell & Brittany Formatters (#1620)

This fixes an issue where the `stylish-haskell` & `brittany` plugins
weren't being added to the enabled plugins list, even if HLS was
compiled with their specific flags or the `all-formatters` flag.

Also removed the AGPL flag checking when adding the `brittany` plugin,
since that is no longer defined anywhere.

Co-authored-by: Potato Hatsue <1793913507@qq.com>
Co-authored-by: Junyoung/Clare Jang <jjc9310@gmail.com>

Author: 3 people

exe/Plugins.hs

@@ -110,7 +110,7 @@ idePlugins includeExamples = pluginDescToIdePlugins allPlugins
 #if retrie
       Retrie.descriptor "retrie" :
 #endif
-#if AGPL && brittany
+#if brittany
       Brittany.descriptor "brittany" :
 #endif
 #if class

haskell-language-server.cabal

@@ -264,10 +264,12 @@ common ormolu
 common stylishHaskell
   if flag(stylishHaskell) || flag(all-formatters)
     build-depends: hls-stylish-haskell-plugin ^>= 1.0.0.0
+    cpp-options: -DstylishHaskell
 
 common brittany
   if (flag(brittany) || flag(all-formatters))
     build-depends: hls-brittany-plugin ^>= 1.0.0.0
+    cpp-options: -Dbrittany
 
 executable haskell-language-server
   import:             common-deps