docs: add doc-comments to new errors

src/error.rs

@@ -13,7 +13,8 @@ pub enum LibError {
     IoError(std::io::Error),
     /// URL parse or check error
     InvalidUrlError(InvalidUrl),
-    ///
+    /// DNS provided no suitable records
+    /// (e. g. domain does not exist)
     HostLookupError,
     /// Response status code is out of [10; 69] range
     StatusOutOfRange(u8),
@@ -22,10 +23,10 @@ pub enum LibError {
     DataNotUtf8(std::string::FromUtf8Error),
     /// Provided string is not a valid MIME type
     InvalidMime(mime::FromStrError),
-    ///
+    /// Hickory Client error
     #[cfg(feature = "hickory")]
     DnsClientError(HickoryClientError),
-    ///
+    /// Hickory Proto error
     #[cfg(feature = "hickory")]
     DnsProtoError(HickoryProtoError),
 }