Fix punctuation in trust model description (#13140)

options/locale/locale_en-US.ini

@@ -1502,7 +1502,7 @@ settings.trust_model.committer.long = Committer: Trust signatures that match com
 settings.trust_model.committer.desc = Valid signatures will only be marked "trusted" if they match the committer, otherwise they will be marked "unmatched". This will force Gitea to be the committer on signed commits with the actual committer marked as Co-Authored-By: and Co-Committed-By: trailer in the commit. The default Gitea key must match a User in the database.
 settings.trust_model.collaboratorcommitter = Collaborator+Committer
 settings.trust_model.collaboratorcommitter.long = Collaborator+Committer: Trust signatures by collaborators which match the committer
-settings.trust_model.collaboratorcommitter.desc = Valid signatures by collaborators of this repository will be marked "trusted" if they match the committer. Otherwise, valid signatures will be marked "untrusted" if the signature matches the committer and "unmatched" otherwise. This will force Gitea to be marked as the committer on signed commits with the actual committer marked as Co-Authored-By: and Co-Committed-By: trailer in the commit. The default Gitea key must match a User in the database,
+settings.trust_model.collaboratorcommitter.desc = Valid signatures by collaborators of this repository will be marked "trusted" if they match the committer. Otherwise, valid signatures will be marked "untrusted" if the signature matches the committer and "unmatched" otherwise. This will force Gitea to be marked as the committer on signed commits with the actual committer marked as Co-Authored-By: and Co-Committed-By: trailer in the commit. The default Gitea key must match a User in the database.
 settings.wiki_delete = Delete Wiki Data
 settings.wiki_delete_desc = Deleting repository wiki data is permanent and cannot be undone.
 settings.wiki_delete_notices_1 = - This will permanently delete and disable the repository wiki for %s.