docs: fix broken link to issues in CONTRIBUTING.md (#2625)

Co-authored-by: Luffy <[email protected]>

Author: Gilbertode-iden254

CONTRIBUTING.md

@@ -9,7 +9,7 @@ We welcome any type of contribution, not only code. You can help with
 - **QA**: file bug reports, the more details you can give the better (e.g. screenshots with the console open)
 - **Marketing**: writing blog posts, howto's, printing stickers, ...
 - **Community**: presenting the project at meetups, organizing a dedicated meetup for the local community, ...
-- **Code**: take a look at the [open issues](issues). Even if you can't write code, commenting on them, showing that you care about a given issue matters. It helps us triage them.
+- **Code**: take a look at the [open issues](https://github.com/docsifyjs/docsify/issues). Even if you can't write code, commenting on them, showing that you care about a given issue matters. It helps us triage them.
 - **Money**: we welcome financial contributions in full transparency on our [open collective](https://opencollective.com/docsify).
 
 ## Your First Contribution
@@ -70,7 +70,7 @@ Anyone can file an expense. If the expense makes sense for the development of th
 
 ## Questions
 
-If you have any questions, create an [issue](issue) (protip: do a quick search first to see if someone else didn't ask the same question before!).
+If you have any questions, create an [issue](https://github.com/docsifyjs/docsify/issues) (protip: do a quick search first to see if someone else didn't ask the same question before!).
 You can also reach us at [email protected].
 
 ## Credits