“Sign into” is incorrect, it should be “sign in to”.
<!-- English rule, 2016-10-17 -->
<rule id="CONFUSION_OF_SIGN_INTO" name="confusion of sign into/sign">
<pattern>
<token>sign</token>
<token>into</token>
</pattern>
<message>Write <suggestion>sign in to</suggestion> when your intention is to write <suggestion>log in to</suggestion> or <suggestion>log on to</suggestion> some website or computer.
Write <suggestion>sign in to</suggestion>, <suggestion>log in to</suggestion> or <suggestion>log on to</suggestion> instead.</message>
<short>Grammatical Mistake.</short>
<example correction='sign in to'>Please <marker>sign into</marker>Firefox.</example>
<example>Please sign in to Firefox.</example>
</rule>
Please modify accordingly and add it to the repository.