docs: use "at least" instead of "more than" in supermajority check comment (leanEthereum#424)

* chore: use "at least" instead of "more than" in comment

* chore: fix typo

* docs: clarify some parts in docs/

Author: MegaRedHand

docs/client/chain.md

@@ -74,8 +74,8 @@ configuration.
 
 ## Chain Justification
 
-Blocks become justified when enough validators attestation for them. Justification
-happens when 2/3 of validators agree.
+Blocks become justified when enough validators attest for them. Justification
+happens when at least 2/3 of validators agree.
 
 Not every slot can be justified. Certain slots are special based on how far
 they are from the last finalized slot. Recent slots are always valid. For

docs/client/forkchoice.md

@@ -52,7 +52,7 @@ consistent views.
 Validators need to know where they can safely submit an attestation. The safe target mechanism
 finds the latest block that has enough support.
 
-A block needs attestations from 2/3 of validators to be safe. This threshold ensures
+A block needs attestations from at least 2/3 of validators to be safe. This threshold ensures
 that conflicting blocks can't both be safe simultaneously.
 
 ## Computing Attestation Targets

docs/client/validator.md

@@ -91,7 +91,7 @@ checkpoint.
 
 ### Why Attest
 
-Attestations drive justification and finalization. When 2/3 of validators attestation for the
+Attestations drive justification and finalization. When at least 2/3 of validators attest for the
 same target, it becomes justified. Justification eventually leads to
 finalization.
 

src/lean_spec/subspecs/containers/state/state.py

@@ -602,7 +602,7 @@ def process_attestations(
 
             # Check whether the vote count crosses the supermajority threshold.
             #
-            # A block becomes justified when more than two-thirds of validators
+            # A block becomes justified when at least two-thirds of validators
             # have voted for it.
             #
             # We compare integers to avoid floating-point division: