chore(package): refresh Hex description

- align the mix project description with the public slackbotws.com positioning
- call out that SlackBot WS handles reconnects, backoff, rate limits, and parsing for Socket Mode bots
- keep the Hex/HexDocs copy honest while making the value prop clearer to developers browsing the package

Author: dfeuerbach

mix.exs

@@ -73,8 +73,8 @@ defmodule SlackBot.MixProject do
 
   defp description do
     """
-    Production-ready Slack bot framework for Socket Mode. Tier-aware rate limiting, \
-    deterministic slash-command parsing, and full observability—out of the box.
+    A framework that solves the complexity of Slack bots—reconnects, backoff, tiered \
+    rate limits, slash-command and chat parsing—so you can build the fun bits.
     """
   end