Simplify language and fix spelling

Include example algorithm.

proposals/0005-dns.md

@@ -130,7 +130,7 @@ Name cache entries have four qualifiers: origin (domain name : port), Dat key, f
         - If the two keys differ, then the cached key is replaced: set the current time to the first seen timestamp, and set the expiration timestamp to exactly 30 minutes.
          - If the two keys are identical, renew the cache expiration timestamp using the following algorithm:
 
-           `currentTime + max(30min, min(TTL, min(6months, (firstSeen - currentTime) * 2)))`
+           `currentTime + max(30min, min(TTL, min(6months, (currentTime - firstSeen) * 2)))`
            - Compare these two numbers and choose the smaller. First number: Subtract the first seen timestamp from the current time and multiply by two; add the resulting number to the current timestamp. Second number: add the resolved TTL to the current time.
              - Adjust the number to be at least 30 minutes in the future and no more than 6 months.
              - Set the resulting number as the new expiration timestamp.