fix: update inline assembly documentation to reflect stable Rust support

[crStiv]

Update outdated inline assembly documentation

Fixes incorrect documentation stating that inline assembly requires nightly Rust. Inline assembly was stabilized in Rust 1.59.0 (February 2022).

Changes:

• Updated assembly backend note to specify Rust 1.59+ requirement
• Removed outdated nightly compiler requirement
• Added version requirement to build guide

closes: #XXXX

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• Wrote unit tests
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