Fix typo

Users each have their own situation(s) rather than a single collective
situation

wiki/src/contribute/mission.html

@@ -67,7 +67,7 @@ The Provider: We empower people to use security technology otherwise inaccessibl
 
 <p>We build emancipatory technology to put people in control of their
 digital lives. We make it simple for our users to make informed
-decisions depending on their situation. <strong>The most vulnerable and
+decisions depending on their situations. <strong>The most vulnerable and
 oppressed people are the most in need of privacy and security.</strong></p>
 
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