opm render: update help text to mention that output is a stream to stdout

[joelanford]

Signed-off-by: Joe Lanford joe.lanford@gmail.com

Description of the change:
Update opm render help text:

1. Use file-based catalog terminology instead of "declarative configs"
2. Include the fact that the output is a stream of objects to stdout, not a single object.

Motivation for the change:
General documentation maintenance and to help clarify the format of data that is produced (its a stream of documents, not one document).

Reviewer Checklist

• Implementation matches the proposed design, or proposal is updated to match implementation
• Sufficient unit test coverage
• Sufficient end-to-end test coverage
• Docs updated or added to /docs
• Commit messages sensible and descriptive

[codecov]

Codecov Report

Merging #1056 (499f318) into master (0080ea0) will increase coverage by 0.05%.
The diff coverage is 70.37%.

@@            Coverage Diff             @@
##           master    #1056      +/-   ##
==========================================
+ Coverage   52.06%   52.12%   +0.05%     
==========================================
  Files         102      102              
  Lines        9218     9244      +26     
==========================================
+ Hits         4799     4818      +19     
- Misses       3505     3512       +7     
  Partials      914      914              

Impacted Files	Coverage Δ
alpha/declcfg/load.go	76.52% <70.37%> (-2.13%)	⬇️
alpha/veneer/semver/semver.go	65.02% <0.00%> (+0.49%)	⬆️

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[everettraven]

Looks good to me!

[anik120]

/lgtm

[openshift-ci]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: anik120, everettraven, joelanford

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