Restore multiline formatting of lists in meson files

Applies a workaround to enforce multiline formatting
of lists to reduce code churn introduced in 93a42a5971.

tests/functional/plugins/meson.build

@@ -1,6 +1,9 @@
 libplugintest = shared_module(
   'plugintest',
   'plugintest.cc',
-  dependencies : [ dependency('nix-expr') ],
+  dependencies : [
+    dependency('nix-expr'),
+    # hack for trailing newline
+  ],
   build_by_default : false,
 )

tests/functional/test-libstoreconsumer/meson.build

@@ -1,6 +1,9 @@
 libstoreconsumer_tester = executable(
   'test-libstoreconsumer',
   'main.cc',
-  dependencies : [ dependency('nix-store') ],
+  dependencies : [
+    dependency('nix-store'),
+    # hack for trailing newline
+  ],
   build_by_default : false,
 )