chore: typo in rendezvous TTL upper-bound + additional writing style updates

[salmad3]

Context

• I believe:

  There may be a rendezvous point-specific upper bound on TTL, with a **minimum** such value of 72hrs

  should be:

  There may be a rendezvous point-specific upper bound on TTL, with a **maximum** such value of 72hrs

• General writing style tweaks.