Support top level prefix for both predicates or "huh methods" and scopes

[sai-c-k]

Use case:

steady_state :temperature, scopes: { prefix: true } do
  state 'cold', default: true
end

steady_state :color_temperature, scopes: { prefix: 'color' } do
  state 'cold', default: true
end

material.cold? # which status takes precedence?

Suggestion: support top-level prefix that applies to both "huh methods" AKA predicates and the scopes.

steady_state :temperature do
  state 'cold', default: true
end

steady_state :color_temperature, prefix: :color do
  state 'cold', default: true
end

# Predicates:
material.color_cold?
material.cold?
# Scopes: 
Material.color_cold
Material.cold