[Docs] Update wording for amazonec2_config userdata

[dkeightley]

It appears this argument does not read a file, and expects userdata inline

[a-blender]

userdata is located in the docs in many more places than just this one line. To update the docs, please

• Add your test steps to verify that user data only expects data inline and not via a file. Did you just see this behavior with EC2? With other providers?
• Update all instances of this field in the docs.

[kkaempf]

closing stale PRs.
If you still intend to work on this, please reopen.

[dkeightley]

Sorry, just got alerted to this.

userdata is located in the docs in many more places than just this one line. To update the docs, please

* Add your test steps to verify that `user data` only expects data inline and not via a file. Did you just see this behavior with EC2? With other providers?

If my interpretation is accurate, the provider is not copying the file or contents, but passing the value as a string to the API, so providing a file would be unusual, the API schema appears to align.

Here's an example I built some time back: https://gist.github.com/dkeightley/6e8e3de9567e2ca9c63294171d45c828#file-main-tf-L70-L76

* Update all instances of this field in the docs.

I'll check through the other node drivers if you agree this is a desired change @a-blender?

[dkeightley]

Reopening as per the above, please close if this change is not desired.