Release notes for 0.75 (#746)

* Release notes for `0.75`

Please add your important new features and breaking changes to the release notes by committing to/opening a PR against the `release-notes-0.75` branch. Thank you!

* Add my changes (#747)

* document 7883 for release notes (#755)

* Add main in modules note

* Add missing PR link

* Add link to breaking unicode literal change

* Fix breaking changes list for now

* Add enumerate commands; Minor reword

* Update breaking changes (webstuff)

* Add detailed changelog

* Reorder sections

* Reorder sections; Add release summary.

* Add breaking changes

* Fix excerpt

* breaking http, progress bar, excerpt update

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Co-authored-by: Leon <[email protected]>
Co-authored-by: Bob Hyman <[email protected]>
Co-authored-by: Jakub Žádník <[email protected]>