[FEATURE REQUEST] Support for LET function

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The LET function assigns names to calculation results. This allows storing intermediate calculations, values, or defining names inside a formula. These names only apply within the scope of the LET function. Similar to variables in programming, LET is accomplished through Excel’s native formula syntax.
Document here: https://support.microsoft.com/en-us/office/let-function-34842dd8-b92b-4d3f-b325-b8b8f9908999#:~:text=Similar%20to%20variables%20in%20programming,LET%20supports%20up%20to%20126.