Metric Stream attribute quirks and features about docs-website

[github-actions]

Hi @keegoid-nr 👋

Thank you for filing an issue! We'll triage your issue and let you know if we have questions, and then route it to the appropriate team so we can get it solved.

[akristen]

Hi @keegoid-nr! Let me confirm the scope of the problem and your proposed fix so I can accurately convey it in a jira:

• We have an existing doc that covers different dimensional metric formats and what attributes correspond with those dim. metrics
• The problem: The doc has an incomplete list of what .byXYZ exist
• The problem: There is little explanation about what these attributes represent
• Solution: update docs to include the missing attribute

I have some follow up questions:

• You mention a missing attribute and that it's related to WHERE entity.type = 'AWS_LAMBDA_REGION'. I'm assuming this is another .BY attribute. Do you know what that is?
• I'm a little lost on what actions customers are meant to take to sidestep NULL. -
• Do they need to manually add the .BY attributes?
• Do they just 'need to know' that NULL always means `WHERE entity.type = 'AWS_LAMBDA_REGION'?

It might be best we hop on call and go over this doc together.

[akristen]

Met with @keegoid-nr and created PR to address this confusion here: #15328

[keegoid-nr]

@akristen There is another PR as well made by engineering: #15290