Reports GDScript variable and constant declarations that miss an explicit type hint when it can be inferred, and flags typed use of the := assignment.

Notes:

• Suggests adding a type when the initializer expression has a concrete, non-Variant/null type.
• Ignores resource-like types that cannot be resolved precisely.
• The := assignment cannot be used together with an explicit type hint. Use = when a type is specified.

Example:

var hp = 100          # suggests: var hp: int = 100
var hp: int := 100    # error: ":=" assignment cannot be typed
var hp: int = 100     # OK