Give more guarntees about ImplicitParams (#23289)

Added new points into description of ImplicitParams into GHC user's guide to fix the #23289 (closed) issue.

• ensure that your commits are either individually buildable or squashed
• ensure that your commit messages describe what they do (referring to tickets using #NNNN syntax when appropriate)
• add a [testcase to the testsuite][adding test].
• updates the users guide if applicable

@simonpj, hi! Can you please review the MR and check the wording?

approved this merge request

Looks great thank you

assigned to @marge-bot

I will attempt to batch this MR (!10340 (closed))...

Batch MR !10340 (closed) failed: CI failed! I will retry later...

I will attempt to batch this MR (!10341 (closed))...

Merged in 74c55712

closed

mentioned in issue #23289 (closed)