math.big: stronger asserts to reduce risks of aliasing

lib/std/math/big/int.zig

@@ -17,7 +17,6 @@ const Endian = std.builtin.Endian;
 const Signedness = std.builtin.Signedness;
 const native_endian = builtin.cpu.arch.endian();
 
-
 // Comptime-computed constants for supported bases (2 - 36)
 // all values are set to 0 for bases 0 - 1, to make it possible to
 // access a constant for a given base b using `constants.value[b]`
@@ -39,7 +38,6 @@ const constants: Constants = blk: {
     break :blk Constants{ .big_bases = bases, .digits_per_limb = digits_per_limb };
 };
 
-
 /// Returns the number of limbs needed to store `scalar`, which must be a
 /// primitive integer or float value.
 /// Note: A comptime-known upper bound of this value that may be used