better description of Weblate automatic suggestion sources

[orangesunny]

differentiation of Weblate and Weblate TM

Proposed changes

Checklist

• [ ] Lint and unit tests pass locally with my changes.
• [ ] I have added tests that prove my fix is effective or that my feature works.
• [ ] I have added documentation to describe my feature.
• [ ] I have squashed my commits into logic units.
• [x] I have described the changes in the commit messages.

Other information

[orangesunny]

@nijel, please verify the description and correct the formatting if needed

[nijel]

Merged, thanks for your contribution!