docs(plugins) Update define-plugin.md (#1977)

Author: foreheadSniffer

src/content/plugins/define-plugin.md

@@ -41,7 +41,7 @@ console.log('Running App version ' + VERSION);
 if(!BROWSER_SUPPORTS_HTML5) require('html5shiv');
 ```
 
-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 either alternate quotes, such as `'"production"'`, or by using `JSON.stringify('production')`.
+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__