f revert useless diff to DRY code back up

Author: TheBlueMatt

lightning/src/onion_message/dns_resolution.rs

@@ -201,11 +201,6 @@ pub struct HumanReadableName {
 	domain_len: u8,
 }
 
-/// Check if the chars in `s` are allowed to be included in a hostname.
-pub(crate) fn str_chars_allowed(s: &str) -> bool {
-	s.chars().all(|c| c.is_ascii_alphanumeric() || c == '.' || c == '_' || c == '-')
-}
-
 impl HumanReadableName {
 	/// Constructs a new [`HumanReadableName`] from the `user` and `domain` parts. See the
 	/// struct-level documentation for more on the requirements on each.
@@ -220,7 +215,7 @@ impl HumanReadableName {
 		if user.is_empty() || domain.is_empty() {
 			return Err(());
 		}
-		if !str_chars_allowed(&user) || !str_chars_allowed(&domain) {
+		if !Hostname::str_is_valid_hostname(&user) || !Hostname::str_is_valid_hostname(&domain) {
 			return Err(());
 		}
 		let mut contents = [0; 255 - REQUIRED_EXTRA_LEN];