docs: Contribution guidelines (#7443)

* docs: gender neutrality

* docs: gender neutrality

* docs: gender neutrality

* Update docs/docs/concepts/features/identity-brokering.md

Co-authored-by: Tim Möhlmann <tim+github@zitadel.com>

* Update docs/docs/guides/integrate/login-ui/mfa.mdx

Co-authored-by: Tim Möhlmann <tim+github@zitadel.com>

* Update docs/docs/guides/integrate/login-ui/passkey.mdx

Co-authored-by: Tim Möhlmann <tim+github@zitadel.com>

* Update internal/static/i18n/en.yaml

Co-authored-by: Tim Möhlmann <tim+github@zitadel.com>

* Update internal/static/i18n/en.yaml

Co-authored-by: Tim Möhlmann <tim+github@zitadel.com>

---------

Co-authored-by: Tim Möhlmann <tim+github@zitadel.com>

internal/static/i18n/en.yaml

@@ -570,7 +570,7 @@ EventTypes:
     removed: Target deleted
   user:
     added: User added
-    selfregistered: User registered himself
+    selfregistered: User registered themself
     initialization:
       code:
         added: Initialization code generated
@@ -609,7 +609,7 @@ EventTypes:
           failed: Secret check failed
     human:
       added: Person added
-      selfregistered: Person registered himself
+      selfregistered: Person registered themself
       avatar:
         added: Avatar added
         removed: Avatar removed