Document in query operator

website/🔌 Query.md

@@ -30,6 +30,7 @@ P.S.: If you are a developer or have a technical knowledge to read a code and wo
 * `>=` greater than or equals
 * `=~` to match against a regular expression
 * `!=~` does not match this regular expression
+* `in` member of a list (e.g. ` prop in ["foo", "bar"]`)
 
 Further, you can combine multiple of these with `and`. Example `prop =~ /something/ and prop != “something”`.