Merge pull request #3476 from zhiqiangxu/fix_wording_about_slashing

fix wording about slashing: "can slashable" => "can be slashable"

specs/phase0/validator.md

@@ -606,7 +606,7 @@ def get_aggregate_and_proof_signature(state: BeaconState,
 
 "Slashing" is the burning of some amount of validator funds and immediate ejection from the active validator set. In Phase 0, there are two ways in which funds can be slashed: [proposer slashing](#proposer-slashing) and [attester slashing](#attester-slashing). Although being slashed has serious repercussions, it is simple enough to avoid being slashed all together by remaining _consistent_ with respect to the messages a validator has previously signed.
 
-*Note*: Signed data must be within a sequential `Fork` context to conflict. Messages cannot be slashed across diverging forks. If the previous fork version is 1 and the chain splits into fork 2 and 102, messages from 1 can slashable against messages in forks 1, 2, and 102. Messages in 2 cannot be slashable against messages in 102, and vice versa.
+*Note*: Signed data must be within a sequential `Fork` context to conflict. Messages cannot be slashed across diverging forks. If the previous fork version is 1 and the chain splits into fork 2 and 102, messages from 1 can be slashable against messages in forks 1, 2, and 102. Messages in 2 cannot be slashable against messages in 102, and vice versa.
 
 ### Proposer slashing