Fix some typos in comments (#1238)

Signed-off-by: momantech <cuimoman@qq.com>

lib/Echidna/Campaign.hs

@@ -60,7 +60,7 @@ isSuccessful =
 
 -- | Run all the transaction sequences from the corpus and accumulate campaign
 -- state. Can be used to minimize corpus as the final campaign state will
--- contain minized corpus without sequences that didn't increase the coverage.
+-- contain minimized corpus without sequences that didn't increase the coverage.
 replayCorpus
   :: (MonadIO m, MonadThrow m, MonadRandom m, MonadReader Env m, MonadState WorkerState m)
   => VM Concrete RealWorld -- ^ VM to start replaying from

lib/Echidna/Exec.hs

@@ -128,7 +128,7 @@ execTxWith executeTx tx = do
                     liftIO $ atomicWriteIORef cacheRef $ Map.insert addr (Just contract) cache
                   _ -> do
                     -- TODO: better error reporting in HEVM, when intermmittent
-                    -- network eror then retry
+                    -- network error then retry
                     liftIO $ atomicWriteIORef cacheRef $ Map.insert addr Nothing cache
                     logMsg $ "ERROR: Failed to fetch contract: " <> show q
                     -- TODO: How should we fail here? It could be a network error,

lib/Echidna/Solidity.hs

@@ -66,7 +66,7 @@ readSolcBatch d = do
       Left e ->
         error $ "Failed to parse combined JSON file " <> (d </> f) <> "\n" <> e
 
--- | Given a list of files, use its extenstion to check if it is a precompiled
+-- | Given a list of files, use its extension to check if it is a precompiled
 -- contract or try to compile it and get a list of its contracts and a list of source
 -- cache, throwing exceptions if necessary.
 compileContracts