Replace argument with parameter in gallery examples and tutorials

[willschlitzer]

As discussed in #886, this pull requests updates the incorrect use of "argument" with "parameter." It covers the the gallery examples and tutorials, except for the files changed in #921 and #922.

Reminders

• Run make format and make check to make sure the code follows the style guide.
• Add tests for new features or tests that would have caught the bug that you're fixing.
• Add new public functions/methods/classes to doc/api/index.rst.
• Write detailed docstrings for all functions/methods.
• If adding new functionality, add an example to docstrings or tutorials.

Slash Commands

You can write slash commands (/command) in the first line of a comment to perform
specific operations. Supported slash commands are:

• /format: automatically format and lint the code
• /test-gmt-dev: run full tests on the latest GMT development version

[seisman]

I only checked the changes you made (not the full documentation). They look good to me.

[seisman]

This PR should be good to merge if @meghanrjones has no further comments.

[weiji14]

Wait, can we merge @michaelgrund's #922 into this one?

[willschlitzer]

Wait, can we merge @michaelgrund's #922 into this one?

I could manually add it in. I just didn't want to step on his toes since he had already opened the PR.

[seisman]

Wait, can we merge @michaelgrund's #922 into this one?

I could manually add it in. I just didn't want to step on his toes since he had already opened the PR.

See his comment at #922 (comment).

[willschlitzer]

Made the changes in #922 and #921.