Use smaller headings for reference and contributors to make them less…

… prominent

README.md

@@ -12,11 +12,11 @@ Follow the guide to [start building on mainnet](./tutorial/README.md).
 
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-# References
+## References
 __[For more information, check the reference page](/tutorial/REFERENCE.md)__
 
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-# Contributors
+## Contributors
 
 For people looking to contribute to the repository, please __[click here](./CONTRIBUTORS.md)__