Update modbus text, with warning (relevant for V1.08)

[janiversen]

Proposed change

pymodbus issues a silly warning, that confuses our users, text is therefore updated to inform users that the warning has no effect on the integration.

Also added a section about how to make a communication debug log, which helps solve issues.

This change is relevant for version 1.0.8 and later.

Type of change

• Spelling, grammar or other readability improvements (current branch).
• [x ] Adjusted missing or incorrect information in the current documentation (current branch).
• Added documentation for a new integration I'm adding to Home Assistant (next branch).
  • I've opened up a PR to add logo's and icons in Brands repository.
• Added documentation for a new feature I'm adding to Home Assistant (next branch).
• Removed stale or deprecated documentation.

Additional information

• Link to parent pull request in the codebase:
• Link to parent pull request in the Brands repository:
• This PR fixes or closes issue:

Checklist

• This PR uses the correct branch, based on one of the following:
  • I made a change to the existing documentation and used the current branch.
  • I made a change that is related to an upcoming version of Home Assistant and used the next branch.
• The documentation follows the Home Assistant documentation standards.

[fabaff]

Thanks