Fix memory leak and warning (#967)

Author: ehuss

Cargo.lock

@@ -46,7 +46,7 @@ ws = { version = "0.8", optional = true}
 
 # Search feature
 elasticlunr-rs = { version = "2.3", optional = true, default-features = false }
-ammonia = { version = "2.1", optional = true }
+ammonia = { version = "2.1.2", optional = true }
 
 [dev-dependencies]
 select = "0.4"