web: fix duplicate package.yaml keys warned about by hpack

hledger-web/package.yaml

@@ -58,16 +58,15 @@ flags:
     manual: false
     default: true
 
+ghc-options:
+- -Wall
+- -fwarn-tabs
+
 when:
 - condition: (flag(dev)) || (flag(library-only))
   cpp-options: -DDEVELOPMENT
 - condition: flag(dev)
   ghc-options: -O0
-
-ghc-options:
-- -Wall
-- -fwarn-tabs
-when:
 - condition: impl(ghc >=8)
   ghc-options:
   - -Wcompat
@@ -152,7 +151,6 @@ executables:
       buildable: false
     - condition: flag(threaded)
       ghc-options: -threaded
-    when:
     - condition: os(darwin) && impl(ghc < 8.0)
       buildable: false