core/crypto: Expose the block sizes for every hash algorithm

While I just went and made this private, this information is required
for keying HMAC.

core/crypto/sm3/sm3.odin

@@ -18,9 +18,12 @@ import "core:encoding/endian"
 import "core:math/bits"
 import "core:mem"
 
-// DIGEST_SIZE is the SM3 digest size.
+// DIGEST_SIZE is the SM3 digest size in bytes.
 DIGEST_SIZE :: 32
 
+// BLOCK_SIZE is the SM3 block size in bytes.
+BLOCK_SIZE :: 64
+
 // Context is a SM3 instance.
 Context :: struct {
 	state:     [8]u32,
@@ -133,9 +136,6 @@ reset :: proc(ctx: ^Context) {
     SM3 implementation
 */
 
-@(private)
-BLOCK_SIZE :: 64
-
 @(private)
 IV := [8]u32 {
 	0x7380166f, 0x4914b2b9, 0x172442d7, 0xda8a0600,