docs: Remove random string in examples, fix quotes

[jonkeane]

The string isn't actually an issue (since it's made up), but it was caught in secret scanning. IMO it's nice(r) to be explicit about what one puts there (hence {your API key} rather than a random string that could (in shape at least) be an API key, but have the person figure out that's the thing that goes there.

I also fixed up some really wonky quotes. They were in comments so I'm not surprised nothing complained about this, but the lacking a quote and then one having double was really strange!

[github-actions]

☂️ Python Coverage

current status: ✅

Overall Coverage

Lines	Covered	Coverage	Threshold	Status
1998	1884	94%	0%	🟢

New Files

No new covered files...

Modified Files

File	Coverage	Status
src/posit/connect/client.py	99%	🟢
TOTAL	99%	🟢

updated for commit: ad9ad2b by action🐍

[jonkeane]

I've swapped over to os.getenv("CONNECT_API_KEY") since we want to encourage that (and not have API keys leak into people's history).

[tdstein]

os.getenv("CONNECT_API_KEY") is the default behavior, so maybe os.getenv("SOMEOTHERNAME") might be slightly more informational. But, it's fine to leave as is. Thanks for grabbing this!