Improve snapshots.md content

[runleonarun]

Contributions

• I have read the contribution docs, and understand what's expected of me.

Link to the page on docs.getdbt.com requiring updates

https://docs.getdbt.com/docs/building-a-dbt-project/snapshots

What part(s) of the page would you like to see updated?

• Move content out of details tabs
• Can we reconfigure this content to make it easier to read?
• Add the following context requested from @pofl

I do want to make a small request here. The docs do not mention what type the updated_at field of the timestamp strategy should have. timestamp types work, of course. But what about ISO date strings and unix epoch integers? Please add this (one sentence) to the docs. You can even hijack this PR to add that.

Additional information

Pulling this out of the PR I started a while back.

[mirnawong1]

closing this as addressed in #6746