Improve the IDLE doc entry for the Format / Format Paragraph menu item, based on this discuss topic.
- Define 'paragraph' to better match what is dependably handled as more or less expected. In particular, specify equal indents.
- Mention that indent of result is indent of paragraph.
- And how to modify max length.
- And to not rewrap code.
I consider the last point to be implicit in the current entry and more obviously so in the revision already prepared. I included it in the initial version but will consider removing it after more discussion.