Fix typos (#13433)

* Update README.md

* Update README.md

* op-supervisor: fix typo in README.md

---------
Co-authored-by: protolambda <proto@protolambda.com>

op-proposer/README.md

@@ -36,7 +36,7 @@ go run ./op-proposer/cmd \
       --game-type=changeme
 ```
 
-See [Proposer Configuration docs] for customization of the transaction-managent,
+See [Proposer Configuration docs] for customization of the transaction-management,
 and usage of a remote signer to isolate the proposer secret key.
 
 On test networks, `--allow-non-finalized` may be used to make proposals sooner, to reduce test time.

op-supervisor/README.md

@@ -271,7 +271,7 @@ Full support for chain reorgs (detecting them, and resolving them) is the
 next priority after the above architecture and data changes.
 
 Further background on the design-choices of op-supervisor can be found in the
-[superchain backend desgin-doc](https://github.com/ethereum-optimism/design-docs/blob/main/protocol/superchain-backend.md).
+[superchain backend design-doc](https://github.com/ethereum-optimism/design-docs/blob/main/protocol/superchain-backend.md).
 
 ## Design principles