Add i2s usage for writing to the dma buffer.

[DivineGod]

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Submission Checklist 📝

• I have updated existing examples or added new ones (if applicable).
• I have used cargo xtask fmt command to ensure that all changed code is formatted correctly.
• I have added changelog entries and/or migration guide notes in the sections below, or I will ask a maintainer to add the skip-changelog or manual-changelog label as appropriate.
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Pull Request Details 📖

Description

This is in response to having issues upgrading from 1.1.0 to 1.2.0 #6275 I have added a section to the I2S module level documentation about writing to the I2S DMA Buffer.

Testing

I tested the changes to the documentation by creating a reproduction repository.

There's a branch for esp-hal 1.1.0, esp-hal 1.2.0, and for async esp-hal 1.2.0. All tested on an esp32c6 device.

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Changelog

esp-hal

• Added: Module level documentation for I2S write.

[bjoernQ]

to have this usage example aligned with the RX example (and show more of the API surface) it would be better to check available_bytes like the RX example does