chore: Update AppiumOptions.cs: Fix typos

[limuyuan]

List of changes

No major changes, just fixed some small wording issues

Types of changes

What types of changes are you proposing/introducing to the .NET client?
Put an x in the boxes that apply

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• New feature (non-breaking change which adds value to the project)
• Breaking change (fix or feature that would cause existing functionality not to work as expected)

Documentation

• Have you proposed a file change/ PR with appium to update documentation?

This can be done by navigating to the documentation section on http://appium.io selecting the appropriate command/endpoint and clicking the 'Edit this doc' link to update the C# example

Integration tests

• Have you provided integration tests to pass against the beta version of appium? (for Bugfix or New feature)

Details

Please refer to file diff

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: limuyuan / name: Morris Li (dd600cd)