Is your feature request related to a problem? Please describe.
We have tools where we want to annotate a value with multiple tags to define certain behaviour

Describe the solution you'd like
We would like to propose a new option parser.AllowMultipleTags(), similar to parser.AllowDuplicateMapKey().

Describe alternatives you've considered
Create cross product of all our possible tags, but this grows quite quickly.

Additional context

An example input file:

a: !default !smart "{{ 2 + 2 }}"
#           ^ This is not allowed currently