docs: add description of IBC to docs/ibc/overview.md (#10778)

## Description

now that Vega upgrade has passed and IBC is a standalone module, a clear definition of the IBC project is needed more than ever. This helpful plain language description helps visitors understand IBC. 

It's funny that I haven't submitted this fix before since I get frustrated every time I visit the [IBC Overview](https://docs.cosmos.network/master/ibc/overview.html) doc and don't find the answer to the heading question `What is the Inter-Blockchain Communication Protocol (IBC)?`

Let's add a description of IBC following that question

---

### Author Checklist

*All items are required. Please add a note to the item if the item is not applicable and
please add links to any relevant follow up issues.*

I have...

- [ ] included the correct [type prefix](https://github.com/commitizen/conventional-commit-types/blob/v3.0.0/index.json) in the PR title
- [ ] added `!` to the type prefix if API or client breaking change
- [ ] targeted the correct branch (see [PR Targeting](https://github.com/cosmos/cosmos-sdk/blob/master/CONTRIBUTING.md#pr-targeting))
- [ ] provided a link to the relevant issue or specification
- [ ] followed the guidelines for [building modules](https://github.com/cosmos/cosmos-sdk/blob/master/docs/building-modules)
- [ ] included the necessary unit and integration [tests](https://github.com/cosmos/cosmos-sdk/blob/master/CONTRIBUTING.md#testing)
- [ ] added a changelog entry to `CHANGELOG.md`
- [ ] included comments for [documenting Go code](https://blog.golang.org/godoc)
- [ ] updated the relevant documentation or specification
- [ ] reviewed "Files changed" and left comments if necessary
- [ ] confirmed all CI checks have passed

### Reviewers Checklist

*All items are required. Please add a note if the item is not applicable and please add
your handle next to the items reviewed if you only reviewed selected items.*

I have...

- [ ] confirmed the correct [type prefix](https://github.com/commitizen/conventional-commit-types/blob/v3.0.0/index.json) in the PR title
- [ ] confirmed `!` in the type prefix if API or client breaking change
- [ ] confirmed all author checklist items have been addressed 
- [ ] reviewed state machine logic
- [ ] reviewed API design and naming
- [ ] reviewed documentation is accurate
- [ ] reviewed tests and test coverage
- [ ] manually tested (if applicable)

docs/ibc/overview.md

@@ -8,7 +8,9 @@ Learn what IBC is, its components, and use cases. {synopsis}
 
 ## What is the Inter-Blockchain Communication Protocol (IBC)?
 
-This document is a guide for developers who want to write their own IBC apps for custom use cases.
+The Inter-Blockchain Communication protocol (IBC) allows blockchains to talk to each other. The backbone of the Cosmos ecosystem, IBC handles transport across different sovereign blockchains. This end-to-end, connection-oriented, stateful protocol provides reliable, ordered, and authenticated communication between heterogeneous blockchains. 
+
+This IBC implementation in Golang is built as a Cosmos SDK module. This document is a guide for developers who want to write their own IBC apps for custom use cases.
 
 The modular design of the IBC protocol means that IBC app developers do not require in-depth knowledge of the low-level details of clients, connections, and proof verification. This brief explanation of the lower levels of the stack is provided so that app developers can gain a high-level understanding of the IBC protocol.