Fix grammatical error in triangulate docs

[willschlitzer]

This pull request fixes a minor grammatical error in the doc string of the function triangulate.

Fixes #

Reminders

• Make sure that your code follows our style. Use the other functions/files as a basis.
• Add tests for new features or tests that would have caught the bug that you're fixing.
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[willschlitzer]

I noticed this typo when I reviewed the pygmt triangulate PR. I proposed changing

performs Delaunay triangulation, i.e., it find how the points should be connected to give the most equilateral triangulation possible
to
performs Delaunay triangulation to find how the points should be connected to create the most equilateral triangulation possible

I think the latter version reads better, but the change I have pushed so far in this PR is just fixing the grammar on "find".

[PaulWessel]

thanks!