Updated FAQ

FAQ.md

@@ -1851,6 +1851,12 @@ Matching is not case sensitive, unless you use [regular expressions](https://en.
 Please see [here](https://developer.android.com/reference/java/util/regex/Pattern) for the documentation of Java regular expressions.
 You can test a regex [here](https://regexr.com/).
 
+Note that a regular expression supports an *or* operator, so if you want to match multiple senders, you can do this:
+
+``
+alice@example.org|bob@example.org|carol@example.org
+``
+
 Note that [dot all mode](https://developer.android.com/reference/java/util/regex/Pattern#DOTALL) is enabled
 to be able to match [unfolded headers](https://tools.ietf.org/html/rfc2822#section-3.2.3).