YAML file: a.yml
  YAML document
    YAML mapping
      YAML key value
        PsiElement(scalar key)('code')
        PsiElement(:)(':')
        PsiElement(Eol)('\n')
        PsiElement(indent)('  ')
        YAML plain scalar text
          PsiElement(text)('src="keys/{{item}}"')
          PsiElement(Eol)('\n')
          PsiElement(indent)('  ')
          PsiElement(text)('mode=0600')
      PsiElement(Eol)('\n')
      YAML key value
        PsiElement(scalar key)('with_items')
        PsiElement(:)(':')
        PsiElement(Eol)('\n')
        PsiElement(indent)('  ')
        YAML sequence
          YAML sequence item
            PsiElement(-)('-')
            PsiWhiteSpace(' ')
            YAML quoted text
              PsiElement(scalar dstring)('"id_rsa.pub"')
  PsiElement(Eol)('\n')