all: change optional to result in most of the libraries (#16123)

vlib/crypto/sha256/sha256.v

@@ -90,7 +90,7 @@ pub fn new224() &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