## Issue being fixed or feature implemented
## What was done?
Added RPC `cleardiscouraged` which clears internally the list of
discouraged peers.
Note: Implementation of a `listdiscouraged` RPC is not possible because
the internal data structure used for discouraged peers is a Bloom
filter.
## How Has This Been Tested?
## Breaking Changes
## Checklist:
- [x] I have performed a self-review of my own code
- [ ] I have commented my code, particularly in hard-to-understand areas
- [ ] I have added or updated relevant unit/integration/functional/e2e
tests
- [x] I have made corresponding changes to the documentation
**For repository code-owners and collaborators only**
- [x] I have assigned this pull request to a milestone
