Minor docs copyedits

[wkalt]

Fixes some copyediting and markdown formatting issues I encountered while reading the chroma docs.

Description of changes

Summarize the changes made by this PR.

1. Dedent example python code snippets in client docs
2. Remove code formatting on JS doc Returns section headers, and downgrade returns/parameters section headers to bolded text.
3. Minor spelling and copyedits.

Test plan

How are these changes tested?
N/A

Documentation Changes

Are all docstrings for user-facing APIs updated if required? Do we need to make documentation changes in the docs repository?
No updates required.

[github-actions]

Reviewer Checklist

Please leverage this checklist to ensure your code review is thorough before approving

Testing, Bugs, Errors, Logs, Documentation

• Can you think of any use case in which the code does not behave as intended? Have they been tested?
• Can you think of any inputs or external events that could break the code? Is user input validated and safe? Have they been tested?
• If appropriate, are there adequate property based tests?
• If appropriate, are there adequate unit tests?
• Should any logging, debugging, tracing information be added or removed?
• Are error messages user-friendly?
• Have all documentation changes needed been made?
• Have all non-obvious changes been commented?

System Compatibility

• Are there any potential impacts on other parts of the system or backward compatibility?
• Does this change intersect with any items on our roadmap, and if so, is there a plan for fitting them together?

Quality

• Is this code of a unexpectedly high quality (Readability, Modularity, Intuitiveness)

[wkalt]

These issues are visible on the site; less so on the GH markdown listing.

Check out https://docs.trychroma.com/reference/js-client to gauge how this will behave.