docs: replace links in apps with correct ones (cosmos#1255)

## Description

I noticed that 2 links at the bottom of the applications docs page were not correct.

closes: #XXXX

---

Before we can merge this PR, please make sure that all the following items have been
checked off. If any of the checklist items are not applicable, please leave them but
write a little note why.

- [x] Targeted PR against correct branch (see [CONTRIBUTING.md](https://github.com/cosmos/ibc-go/blob/master/CONTRIBUTING.md#pr-targeting))
- [ ] Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
- [ ] Code follows the [module structure standards](https://github.com/cosmos/cosmos-sdk/blob/master/docs/building-modules/structure.md).
- [ ] Wrote unit and integration [tests](https://github.com/cosmos/ibc-go/blob/master/CONTRIBUTING.md#testing)
- [ ] Updated relevant documentation (`docs/`) or specification (`x/<module>/spec/`)
- [ ] Added relevant `godoc` [comments](https://blog.golang.org/godoc-documenting-go-code).
- [ ] Added a relevant changelog entry to the `Unreleased` section in `CHANGELOG.md`
- [x] Re-reviewed `Files changed` in the Github PR explorer
- [ ] Review `Codecov Report` in the comment section below once CI passes

docs/ibc/apps.md

@@ -464,13 +464,13 @@ which implements everything discussed above.
 Here are the useful parts of the module to look at:
 
 [Binding to transfer
-port](https://github.com/cosmos/ibc-go/blob/main/modules/apps/transfer/types/genesis.go)
+port](https://github.com/cosmos/ibc-go/blob/main/modules/apps/transfer/keeper/genesis.go)
 
 [Sending transfer
 packets](https://github.com/cosmos/ibc-go/blob/main/modules/apps/transfer/keeper/relay.go)
 
 [Implementing IBC
-callbacks](https://github.com/cosmos/ibc-go/blob/main/modules/apps/transfer/module.go)
+callbacks](https://github.com/cosmos/ibc-go/blob/main/modules/apps/transfer/ibc_module.go)
 
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