docs: add jq doc for editing genesis file (#9918)

<!--
The default pull request template is for types feat, fix, or refactor.
For other templates, add one of the following parameters to the url:
- template=docs.md
- template=other.md
-->

## Description

Closes: #9908 

<!-- Add a description of the changes that this PR introduces and the files that
are the most critical to review. -->

---

### 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/run-node/run-node.md

@@ -39,6 +39,24 @@ The `~/.simapp` folder has the following structure:
       |- priv_validator_key.json    # Private key to use as a validator in the consensus protocol.
 ```
 
+## Updating Some Default Settings
+
+If you want to change any field values in configuration files (for ex: genesis.json) you can use `jq` ([installation](https://stedolan.github.io/jq/download/) & [docs](https://stedolan.github.io/jq/manual/#Assignment)) & `sed` commands to do that. Few examples are listed here.
+```bash
+# to change the chain-id
+jq '.chain_id = "testing"' genesis.json > temp.json && mv temp.json genesis.json
+
+# to enable the api server
+sed -i '/\[api\]/,+3 s/enable = false/enable = true/' app.toml
+
+# to change the voting_period
+jq '.app_state.gov.voting_params.voting_period = "600s"' genesis.json > temp.json && mv temp.json genesis.json
+
+# to change the inflation
+jq '.app_state.mint.minter.inflation = "0.300000000000000000"' genesis.json > temp.json && mv temp.json genesis.json
+```
+
+## Adding Genesis Accounts
 Before starting the chain, you need to populate the state with at least one account. To do so, first [create a new account in the keyring](./keyring.md#adding-keys-to-the-keyring) named `my_validator` under the `test` keyring backend (feel free to choose another name and another backend).
 
 Now that you have created a local account, go ahead and grant it some `stake` tokens in your chain's genesis file. Doing so will also make sure your chain is aware of this account's existence: