Fix cosmetic problems in YAML source

This change corrects problems reported by the `yamllint` linter.

Since key duplication problems were removed in 4d48711, this commit
mainly fixes trailing spaces and extra empty lines at beginning/end of
files.

test/integration/targets/templating_settings/test_templating_settings.yml

@@ -13,4 +13,3 @@
   # name goes through templating correctly
     - name: 'Task: {{ a_list | to_json }}'
       debug: msg='{{ a_list | to_json }}'
-