Docs: Fix typos in documentation

[kilavvy]

Description:

This pull request addresses two minor typos found in the project's documentation.

- Corrected "Guidlines" to "Guidelines" in `contributor_docs/documentation_style_guide.md`.
- Corrected "suprises" to "surprises" in `contributor_docs/project_wrapups/elginmclaren_gsoc_2018.md`.

These changes improve the clarity and professionalism of the documentation.

[welcome]

🎉 Thanks for opening this pull request! Please check out our contributing guidelines if you haven't already. And be sure to add yourself to the list of contributors on the readme page!

[perminder-17]

@all-contributors please add @kilavvy for doc

[allcontributors]

@perminder-17

I've put up a pull request to add @kilavvy! 🎉