Adding files to address --clean does not remove the generated docs sub issue of issue 1918.

src/Idris/Package.idr

@@ -843,6 +843,21 @@ clean pkg opts -- `opts` is not used but might be in the future
          deleteFolder builddir []
          maybe (pure ()) (\e => delete (outputdir </> e))
                (executable pkg)
+         -- clean out the generated docs
+         defs <- get Ctxt
+         let build = build_dir (dirs (options defs))
+         let docBase = build </> "docs"
+         let docDir = docBase </> "docs"
+         Right docfiles' <- coreLift $ listDir docDir
+           | Left err => pure ()
+         Right docfiles'' <- coreLift $ listDir docBase
+           | Left err => pure ()
+         traverse_ (\x => delete $ docDir </> x)
+                   docfiles'
+         traverse_ (\x => delete $ docBase </> x)
+                   docfiles''
+         deleteFolder docDir []
+         deleteFolder docBase []
          runScript (postclean pkg)
   where
     delete : String -> Core ()