Fix argument name for state/timeline functions

[syvb]

Description

For the state/timeline aggregates, the name of the argument for the aggregate is written as tws instead of agg in a few parts of the documentation. tws stands for Time-Weighted Summary, which is not applicable here. I think I copied from the time-weighted average documentation and forgot to change the parameter name.

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[github-actions]

Allow 10 minutes from last push for the staging site to build. If the link doesn't work, try using incognito mode instead. For internal reviewers, check web-documentation repo actions for staging build status. Link to build for this PR: http://docs-dev.timescale.com/docs-sv-tws-name-fix