docs(plugins): Move code example related warning to the code blocks (#2638)

Move related code example warning to the code block itself in order to avoid confusion, many come to see how to use `NODE_ENV` so the previous block location was too deep without giving appropriate warning immediately.

Author: EugeneHlushko

src/content/plugins/define-plugin.md

@@ -8,7 +8,8 @@ contributors:
   - smonusbonus
 ---
 
-The `DefinePlugin` allows you to create global constants which can be configured at __compile__ time. This can be useful for allowing different behavior between development builds and release builds. If you perform logging in your development build but not in the release build you might use a global constant to determine whether logging takes place. That's where `DefinePlugin` shines, set it and forget it rules for development and release builds.
+
+The `DefinePlugin` allows you to create global constants which can be configured at __compile__ time. This can be useful for allowing different behavior between development builds and production builds. If you perform logging in your development build but not in the production build you might use a global constant to determine whether logging takes place. That's where `DefinePlugin` shines, set it and forget it rules for development and production builds.
 
 ``` javascript
 new webpack.DefinePlugin({
@@ -44,6 +45,9 @@ console.log('Running App version ' + VERSION);
 if(!BROWSER_SUPPORTS_HTML5) require('html5shiv');
 ```
 
+
+W> When defining values for `process` prefer `'process.env.NODE_ENV': JSON.stringify('production')` over `process: { env: { NODE_ENV: JSON.stringify('production') } }`. Using the latter will overwrite the `process` object which can break compatibility with some modules that expect other values on the process object to be defined.
+
 T> Note that because the plugin does a direct text replacement, the value given to it must include __actual quotes__ inside of the string itself. Typically, this is done either with alternate quotes, such as `'"production"'`, or by using `JSON.stringify('production')`.
 
 __index.js__
@@ -87,8 +91,6 @@ new webpack.DefinePlugin({
 });
 ```
 
-W> When defining values for `process` prefer `'process.env.NODE_ENV': JSON.stringify('production')` over `process: { env: { NODE_ENV: JSON.stringify('production') } }`. Using the latter will overwrite the `process` object which can break compatibility with some modules that expect other values on the process object to be defined.
-
 
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