value.nick_values column isn't long enough #2291

Description

sopel/db.py#L66 states it should be 255 charecters. That doesn't even fit seen which is from core as that needs at least 512. This should be made higher.

Reproduction steps

1. Run bot with mysql/MariaDB
2. Say something long3.
3. See error4.

Expected behavior

Column is big enough

Logs

None yet, I can post if really needed

Environment

• Sopel .version: somewhere between 7 & 8
• Sopel installed via: source
• Python version: 3.9.2
• Operating system: Bullseye
• IRCd /version: Libera
• Relevant plugins: core, seen

Notes

TEXT might be good, moaned on IRC. Will probably make TEXT.