[DOCS] Update dev mode tutorial (#20826)

* Update dev mode tutorial to include connecting to Remix

* Remove mention of ports

* Update Remix steps

docs/_getting-started/dev-mode.md

@@ -3,7 +3,7 @@ title: Dev mode
 sort_key: B
 ---
 
-Geth has a development mode which sets up a single node Ethereum test network with a number of options optimized for developing on local machines. You enable it with the `--dev` argument.
+Geth has a development mode that sets up a single node Ethereum test network with options optimized for developing on local machines. You enable it with the `--dev` argument.
 
 Starting geth in dev mode does the following:
 
@@ -12,13 +12,26 @@ Starting geth in dev mode does the following:
 -   Turns off discovery by other nodes
 -   Sets the gas price to 0
 -   Uses the Clique PoA consensus engine with which allows blocks to be mined as-needed without excessive CPU and memory consumption
--   Uses on-demand block generation, producing blocks when there are transactions waiting to be mined
+-   Uses on-demand block generation, producing blocks when transactions are waiting to be mined
 
-You can specify a data directory to maintain state between runs using the `--datadir` option, otherwise databases are ephemeral and in-memory:
+## Start Geth in Dev Mode
+
+You can specify a data directory to maintain state between runs using the `--datadir` option, otherwise, databases are ephemeral and in-memory:
+
+```shell
+mkdir test-chain-dir
+```
+
+For this guide, start geth in dev mode, and enable [RPC](../_rpc/server.md) so you can connect other applications to geth. For this guide, we use Remix, the web-based Ethereum IDE, so also allow its domains to accept cross-origin requests.
+
+```shell
+geth --datadir test-chain-dir --rpc --dev --rpccorsdomain "https://remix.ethereum.org,http://remix.ethereum.org"
+```
+
+Connect to the IPC console on the node from another terminal window:
 
 ```shell
-$ mkdir test-chain-dir
+geth attach <IPC_LOCATION>
-$ geth --dev --datadir test-chain-dir console
 ```
 
 Once geth is running in dev mode, you can interact with it in the same way as when geth is running in other ways.
@@ -29,7 +42,7 @@ For example, create a test account:
 > personal.newAccount()
 ```
 
-Then transfer ether from the coinbase to the new account:
+And transfer ether from the coinbase to the new account:
 
 ```shell
 > eth.sendTransaction({from:eth.coinbase, to:eth.accounts[1], value: web3.toWei(0.05, "ether")})
@@ -41,8 +54,8 @@ And check the balance of the account:
 > eth.getBalance(eth.accounts[1])
 ```
 
-If you want to test your dapps with a realistic block time use the `--dev.period` option when you start dev mode:
+If you want to test your dapps with a realistic block time use the `--dev.period` option when you start dev mode with the `--dev.period 14` argument.
 
-```shell
+## Connect Remix to Geth
-geth --dev --dev.period 14 console
+
-```
+With geth now running, open <https://remix.ethereum.org>. Compile the contract as normal, but when you deploy and run a contract, select _Web3 Provider_ from the _Environment_ dropdown, and add "http://127.0.0.1:8545" to the popup box. Click _Deploy_, and interact with the contract. You should see contract creation, mining, and transaction activity.