Merge #12716: Fix typos and cleanup in various files

4d9b4256d8 Fix typos (Dimitris Apostolou)

Pull request description:

  Unfortunately I messed up my repo while trying to squash #12593 so I created a PR with just the correct fixes.

Tree-SHA512: 295d77b51bd2a9381f1802c263de7ffb2edd670d9647391e32f9a414705b3c8b483bb0e469a9b85ab6a70919ea13397fa8dfda2aea7a398b64b187f178fe6a06

test/functional/p2p_segwit.py

@@ -1511,7 +1511,7 @@ class SegWitTest(BitcoinTestFramework):
         # Make sure that this peer thinks segwit has activated.
         assert(get_bip9_status(self.nodes[node_id], 'segwit')['status'] == "active")
 
-        # Make sure this peers blocks match those of node0.
+        # Make sure this peer's blocks match those of node0.
         height = self.nodes[node_id].getblockcount()
         while height >= 0:
             block_hash = self.nodes[node_id].getblockhash(height)