Don't use catchall match in is_segwit

Author: LLFourn

src/descriptor/mod.rs

@@ -267,7 +267,7 @@ impl DescriptorType {
         use self::DescriptorType::*;
         match self {
             Wpkh | ShWpkh | Wsh | ShWsh | ShWshSortedMulti | WshSortedMulti | Tr => true,
-            _ => false,
+            Bare | Sh | Pkh | ShSortedMulti => false,
         }
     }
 }