core/crypto: Add more assertions to the low level API

Assertions here are "fine" and it matches what the code that has the
checks in init/update/final already does.

core/crypto/sha3/sha3.odin

@@ -347,7 +347,7 @@ init :: proc(ctx: ^_sha3.Sha3_Context) {
 	_sha3.init(ctx)
 }
 
-update :: proc "contextless" (ctx: ^_sha3.Sha3_Context, data: []byte) {
+update :: proc(ctx: ^_sha3.Sha3_Context, data: []byte) {
 	_sha3.update(ctx, data)
 }