Fix/methods named new

[chharvey]

1. fixes methods named new
   TypeScript treats new(...P): R; in an object type as a constructor signature.
   The caller is then expected to call the method like a constructor,
   e.g. new mod.struct(...args), which is incorrect.

   With that syntax, the method called correctly, mod.struct.new(...args), raises an error:

   Property 'new' does not exist on type 'T'.

   The fix is to make new a regular property with a function type.

2. allows readonly array arguments
   Widens parameter types to include readonly arrays.

   Sometimes a caller may have a readonly array they want to pass
   into a function. If the function expects a writeable array,
   the assignment is not allowed:

   The type 'readonly T[]' is 'readonly' and cannot be assigned to the mutable type 'T[]'.

   That’s good typing, if the function actually mutates the array.
   But if it doesn’t, the parameter type is too narrow, and the caller is forced to use spread syntax, concating/slicing, type casting,
   or other ‘hacky’ techniques to bypass the error.

   By making the parameter type readonly T[],
   we’re promising the caller that the method will never mutate the array.
   I think that’s a reasonable assumption for all these methods.

3. fixes signature of struct.new (parameter operands should be array of ExpressionRef)

4. whitespace cleanup

[MaxGraey]

LGTM

Thanks!