Fix lots of typos.

eth2/types/src/slot_epoch.rs

@@ -1,4 +1,4 @@
-//! The `Slot` and `Epoch` types are defined as newtypes over u64 to enforce type-safety between
+//! The `Slot` and `Epoch` types are defined as new types over u64 to enforce type-safety between
 //! the two types.
 //!
 //! `Slot` and `Epoch` have implementations which permit conversion, comparison and math operations

eth2/types/src/test_utils/builders/testing_deposit_builder.rs

@@ -34,7 +34,7 @@ impl TestingDepositBuilder {
     ///
     /// - `pubkey` to the signing pubkey.
     /// - `withdrawal_credentials` to the signing pubkey.
-    /// - `proof_of_possesssion`
+    /// - `proof_of_possession`
     pub fn sign(&mut self, keypair: &Keypair, epoch: Epoch, fork: &Fork, spec: &ChainSpec) {
         let withdrawal_credentials = Hash256::from_slice(
             &get_withdrawal_credentials(&keypair.pk, spec.bls_withdrawal_prefix_byte)[..],

eth2/types/src/test_utils/test_random/secret_key.rs

@@ -6,7 +6,7 @@ impl TestRandom for SecretKey {
         let mut key_bytes = vec![0; 48];
         rng.fill_bytes(&mut key_bytes);
         /*
-         * An `unreachable!` is used here as there's no reason why you cannot constuct a key from a
+         * An `unreachable!` is used here as there's no reason why you cannot construct a key from a
          * fixed-length byte slice. Also, this should only be used during testing so a panic is
          * acceptable.
          */