Meta issue: collection of things to improve in the docs

[evansd]

The collection of confusing error messages was very helpful; I'm hoping this will be too.

[evansd]

A user wanted to exclude patients with a certain condition from their dataset but didn't know how to do this. As soon as they were shown the logical ~ operator they knew what to do, but they didn't find that when searching for "exclude" and "ignore" and instead found old Cohort Extractor documentation.
https://bennettoxford.slack.com/archives/C04DVD1UQC9/p1708100034802849

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Hopefully addressed in #1936

[evansd]

Second example of a user not knowing how to exclude patients:
https://bennettoxford.slack.com/archives/C04DVD1UQC9/p1708692226021599

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Hopefully addressed in #1936

[evansd]

• Search returns "raw" schemas before other schemas #2086

[evansd]

Some useful feedback on onboarding docs generally which includes several aspects of the ehrQL docs:
opensafely/documentation#1592

Related Slack threads:
https://bennettoxford.slack.com/archives/C63UXGB8E/p1723042936777829
https://bennettoxford.slack.com/archives/C069YDR4NCA/p1723043703481089