docs: drop RFC citations and what-comments, fix stale refs

Apply the no-internal-citation and WHY-not-WHAT rules to source
comments; correct stale identifiers (NewBrowser, PBKDF2Key) and RFC
facts (Yandex ciphertext, Firefox PBKDF2 password).

masterkey/gcoredump_darwin.go

@@ -102,7 +102,6 @@ func DecryptKeychainRecords() ([]keychainbreaker.GenericPassword, error) {
 		return nil, fmt.Errorf("read keychain: %w", err)
 	}
 
-	// try each candidate key against the keychain
 	for _, candidate := range candidates {
 		kc, err := keychainbreaker.Open(keychainbreaker.WithBytes(keychainBuf))
 		if err != nil {
@@ -157,7 +156,6 @@ func scanMasterKeyCandidates(corePath string, regions []addressRange) ([]string,
 			if ptr < region.start || ptr > region.end {
 				continue
 			}
-			// read 24 bytes at the pointer offset
 			offset := ptr - vaddr
 			if offset+0x18 > uint64(len(data)) {
 				continue