fix(mail-overview): don't re-notify the prior batch, flatten newlines

The lastmod range is inclusive at both ends and the stored revision
was reused as the next start, so the batch just notified matched
again. Start one revision later.

A subject can contain a newline, which broke the bullet rows and the
+N more count; flatten CR/LF to a space before escaping.

Also reconciles the state-write comment and spec with the actual
skip-and-advance failure behavior, and corrects two doc wordings.

1 files changed, 1 insertions, 1 deletions

diff --git a/mail-overview/README.md b/mail-overview/README.md
index 6e34140..7465ac1 100644
--- a/mail-overview/README.md
+++ b/mail-overview/README.md
@@ -123,7 +123,7 @@ local index.
 ## Notifications on arrival
 
 `mail-notify.sh` sends one notification per account when mail lands, with the
-newest three senders and subjects and a `+N more` line when the batch is
+newest three threads' sender and subject and a `+N more` line when the batch is
 bigger. Each message is a bullet on its own line with a blank line between,
 under a bold `New Mail` heading with the account and count as the second line.
 Started from `autostart.lua`, it runs for the whole session.