docs(fork-choice): trim drifted numbered overviews in docstrings (#1142)

Two docstrings carried numbered overview lists that duplicated the
method bodies' own labeled section comments and had drifted out of sync.

The attestation validation docstring listed seven checks while the body
has six labeled sections.
The block-processing docstring listed four steps but omitted the
duplicate-data rejection and signature verification the body performs.

Trim each numbered list to a single accurate summary line.
The labeled body comments remain the source of truth.

Docs-only change. just check passes.

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: tcoratger

src/lean_spec/spec/forks/lstar/fork_choice.py

@@ -179,14 +179,7 @@ def validate_attestation(self, store: LstarStore, attestation_data: AttestationD
         """
         Validate incoming attestation before processing.
 
-        Ensures the vote respects the basic laws of time and topology:
-            1. The blocks voted for must exist in our store.
-            2. A vote cannot span backwards in time (source > target).
-            3. The head must be at least as recent as source and target.
-            4. Checkpoint slots must match the actual block slots.
-            5. Source, target, and head must lie on one parent chain.
-            6. The vote's slot cannot precede the slot of the head it claims to have seen.
-            7. The vote's slot must have started locally (a small disparity margin is allowed).
+        Ensures the vote respects the basic laws of time and topology.
 
         Raises:
             SpecRejectionError: If the attestation fails any of the validation checks above.
@@ -528,12 +521,7 @@ def on_block(
         """
         Process a new block and update the forkchoice state.
 
-        This method integrates a block into the forkchoice store by:
-
-        1. Validating the block's parent exists
-        2. Computing the post-state via the state transition function
-        3. Processing attestations included in the block body (on-chain)
-        4. Updating the forkchoice head
+        Integrates a block into the forkchoice store and recomputes the head.
 
         Raises:
             SpecRejectionError: UNKNOWN_PARENT_BLOCK if the parent state is not in the store.