cli: package.yaml: source dir first for clarity

hledger/package.yaml

@@ -163,8 +163,8 @@ library:
 
 executables:
   hledger:
-    main: hledger-cli.hs
     source-dirs: app
+    main: hledger-cli.hs
     cpp-options: -DVERSION="1.3.99"
     when:
     - condition: flag(threaded)
@@ -192,8 +192,8 @@ executables:
 
 tests:
   test:
-    main: test.hs
     source-dirs: test
+    main: test.hs
     cpp-options: -DVERSION="1.3.99"
     dependencies:
     - hledger
@@ -220,8 +220,8 @@ tests:
 
 benchmarks:
   bench:
-    main: bench.hs
     source-dirs: bench
+    main: bench.hs
     dependencies:
     - hledger
     - criterion