docs: fix links to SECURITY and CONTRIBUTING files (#21921)

docs/tutorial/support.md

@@ -3,7 +3,7 @@
 ## Finding Support
 
 If you have a security concern,
-please see the [security document](../../SECURITY.md).
+please see the [security document](https://github.com/electron/electron/tree/master/SECURITY.md).
 
 If you're looking for programming help,
 for answers to questions,
@@ -22,7 +22,7 @@ forums
 - [`electron-pl`](https://electronpl.github.io) *(Poland)*
 
 If you'd like to contribute to Electron,
-see the [contributing document](../../CONTRIBUTING.md).
+see the [contributing document](https://github.com/electron/electron/blob/master/CONTRIBUTING.md).
 
 If you've found a bug in a [supported version](#supported-versions) of Electron,
 please report it with the [issue tracker](../development/issues.md).