Do not disable parallel GC (#1190)

Parallel GC is a win in my machine (16 cores).

Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

Author: pepeiborra

ghcide/ghcide.cabal

@@ -253,9 +253,8 @@ executable ghcide
                 -- allow user RTS overrides
                 -rtsopts
                 -- disable idle GC
-                -- disable parallel GC
                 -- increase nursery size
-                "-with-rtsopts=-I0 -qg -A128M"
+                "-with-rtsopts=-I0 -A128M"
     main-is: Main.hs
     build-depends:
         aeson,

haskell-language-server.cabal

@@ -294,9 +294,8 @@ executable haskell-language-server
     -- allow user RTS overrides
     -rtsopts
     -- disable idle GC
-    -- disable parallel GC
     -- increase nursery size
-    "-with-rtsopts=-I0 -qg -A128M"
+    "-with-rtsopts=-I0 -A128M"
   if flag(pedantic)
     ghc-options: -Werror
 
@@ -341,9 +340,8 @@ executable haskell-language-server-wrapper
     -- allow user RTS overrides
     -rtsopts
     -- disable idle GC
-    -- disable parallel GC
     -- increase nursery size
-    "-with-rtsopts=-I0 -qg -A128M"
+    "-with-rtsopts=-I0 -A128M"
   if flag(pedantic)
     ghc-options: -Werror
 
@@ -468,7 +466,3 @@ test-suite wrapper-test
   hs-source-dirs:     test/wrapper
   main-is:            Main.hs
   ghc-options:        -Wall
-
-
-
-