run codespell throughout fixing typos automagically

=== Do not change lines below ===
{
 "chain": [],
 "cmd": "codespell -w",
 "exit": 0,
 "extra_inputs": [],
 "inputs": [],
 "outputs": [],
 "pwd": "."
}
^^^ Do not change lines above ^^^

Annex/RemoteTrackingBranch.hs

@@ -46,7 +46,7 @@ setRemoteTrackingBranch tb commit =
  -
  - The second parent of the merge commit is the past history of the
  - RemoteTrackingBranch as imported from a remote. When importing a
- - history of trees from a remote, commits can be sythesized from
+ - history of trees from a remote, commits can be synthesized from
  - them, but such commits won't have the same sha due to eg date differing.
  - But since we know that the second parent consists entirely of such
  - import commits, they can be reused when updating the