docs: Add docs for process/web endpoint

[jfahrenkrug]

Add docs that also document the new overwrite parameter. This is related to open-webui/open-webui#21613

[pr-validator-bot]

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[Classic298]

do you want to update this PR since Tim merged a somewhat different version of your PR? If not feel free to close.

[jfahrenkrug]

do you want to update this PR since Tim merged a somewhat different version of your PR? If not feel free to close.

@Classic298 Thank you, I've changed to docs to match the new implementation. This is ready for review now.