crypto.md5: change the Digest.write return type, from ?int to !int (

#19311)

Co-authored-by: Subhomoy Haldar <shaldar@componentsense.com>

vlib/crypto/md5/md5.v

@@ -66,7 +66,7 @@ pub fn new() &Digest {
 }
 
 // write writes the contents of `p_` to the internal hash representation.
-pub fn (mut d Digest) write(p_ []u8) ?int {
+pub fn (mut d Digest) write(p_ []u8) !int {
 	unsafe {
 		mut p := p_
 		nn := p.len