pvf-precheck: update implementers' guide (#4612)

This commit incorporates the changes made to the runtime in the
following PRs:

- https://github.com/paritytech/polkadot/pull/4408
- https://github.com/paritytech/polkadot/pull/4457
- https://github.com/paritytech/polkadot/pull/4540
- https://github.com/paritytech/polkadot/pull/4542
- https://github.com/paritytech/polkadot/pull/4581

Note that this PR does not include the description of the PVF
pre-checker subsystem. This should be addressed within
https://github.com/paritytech/polkadot/issues/4611

Co-authored-by: sandreim <54316454+sandreim@users.noreply.github.com>

polkadot/roadmap/implementers-guide/src/SUMMARY.md

@@ -10,6 +10,7 @@
   - [Chain Selection and Finalization](protocol-chain-selection.md)
 - [Architecture Overview](architecture.md)
   - [Messaging Overview](messaging.md)
+  - [PVF Pre-checking](pvf-prechecking.md)
 - [Runtime Architecture](runtime/README.md)
   - [`Initializer` Module](runtime/initializer.md)
   - [`Configuration` Module](runtime/configuration.md)
@@ -34,6 +35,7 @@
   - [Candidate Events](runtime-api/candidate-events.md)
   - [Disputes Info](runtime-api/disputes-info.md)
   - [Candidates Included](runtime-api/candidates-included.md)
+  - [PVF Pre-checking](runtime-api/pvf-prechecking.md)
 - [Node Architecture](node/README.md)
   - [Subsystems and Jobs](node/subsystems-and-jobs.md)
   - [Overseer](node/overseer.md)
@@ -66,6 +68,7 @@
     - [Runtime API Requests](node/utility/runtime-api.md)
     - [Chain API Requests](node/utility/chain-api.md)
     - [Chain Selection Request](node/utility/chain-selection.md)
+    - [PVF Pre-Checking](node/utility/pvf-prechecker.md)
 - [Data Structures and Types](types/README.md)
     - [Candidate](types/candidate.md)
     - [Backing](types/backing.md)
@@ -77,6 +80,7 @@
     - [Network](types/network.md)
     - [Approvals](types/approval.md)
     - [Disputes](types/disputes.md)
+    - [PVF Pre-checking](types/pvf-prechecking.md)
 
 [Glossary](glossary.md)
 [Further Reading](further-reading.md)