Fix some errors in contributing instructions (#6707)

* Fix some errors in contributing instructions

* fix spacing

CONTRIBUTING.md

@@ -58,14 +58,17 @@ own Github account, and then clone it using SSH. If you haven't already, you may
 to connect to Github with SSH.
 2. Make sure to [configure Git to keep your fork in sync](https://docs.github.com/en/get-started/quickstart/fork-a-repo#configuring-git-to-sync-your-fork-with-the-upstream-repository)
 with the upstream DevTools repo.
-3. Ensure that you have access to the `devtools_tool` executable by adding the `tool/bin` folder to your `PATH` environment variable:
-	- **MacOS Users**
-		- add the following to your `~/.bashrc` file, replacing `<DEVTOOLS_DIR>` with the local path to your DevTools repo:
+3. Ensure that you have access to the `devtools_tool` executable by:
+	- Running `flutter pub get` on the `tool` directory
+	- Adding the `tool/bin` folder to your `PATH` environment variable:
+	  - **MacOS Users**
+	    - add the following to your `~/.zshrc` file (or `~/.bashrc`, `~/.bash_profile` if you use Bash),
+		replacing `<DEVTOOLS_DIR>` with the local path to your DevTools repo:
 
 			```
 			export PATH=$PATH:<DEVTOOLS_DIR>/tool/bin
 			```
-	- **Windows Users**
+	  - **Windows Users**
 		- Open "Edit environment variables for your account" from Control Panel
 		- Locate the `Path` variable and click **Edit**
 		- Click the **New** button and paste in `<DEVTOOLS_DIR>/tool/bin`, replacing `<DEVTOOLS_DIR>`
@@ -171,9 +174,9 @@ command palette (`F1`)) and add the following to your settings:
 "dart.customDevTools": {
 	"path": "/path/to/devtools",
 	"env": {
-		"LOCAL_DART_SDK": "/path/to/dart-sdk/sdk"
+		"LOCAL_DART_SDK": "/path/to/sdk"
 		// Path to the version that Flutter DevTools is pinned to.
-        "FLUTTER_ROOT": "/path/to/devtools/tool/flutter-sdk"
+		"FLUTTER_ROOT": "/path/to/devtools/tool/flutter-sdk"
 	}
 },
 ```

tool/lib/commands/serve.dart

@@ -110,7 +110,7 @@ class ServeCommand extends Command {
     if (localDartSdkLocation == null) {
       throw Exception('LOCAL_DART_SDK environment variable not set. Please add '
           'the following to your \'.bash_profile\' or \'.bashrc\' file:\n'
-          'export LOCAL_DART_SDK=<absolute/path/to/my/dart-sdk/sdk>');
+          'export LOCAL_DART_SDK=<absolute/path/to/my/sdk>');
     }
 
     // Validate the path looks correct in case it was set without the /sdk or
@@ -119,8 +119,7 @@ class ServeCommand extends Command {
     if (!pkgDir.existsSync()) {
       throw Exception(
         'No pkg directory found in LOCAL_DART_SDK at "${pkgDir.path}"\n'
-        'Is LOCAL_DART_SDK set correctly to the dart-sdk${path.separator}sdk '
-        'directory?',
+        'Is LOCAL_DART_SDK set correctly to the "sdk" directory?',
       );
     }