Feature Request: Parameter to expose textual forms of formulas in sheet.

[121GWJolt]

I'm currently in a scenario where I'm trying to read the raw text of a formula and parse out a bit of info from it (which is less than ideal, but it's what I've got to work with. Parsing out image urls from a Google sheet downloaded in XLSX form because CSV never provides them, but some data is only stored on there within image formulas so it displays on sheets).

Currently, ExcelProvider only gives me completely blank fields in those particular cases.

It would be nice if in the type definition we can specify that we want to see the textual form of formulas instead of returning blank. Not asking for evaluation or anything of the sort; just the formula itself.

[ingted]

ExcelDataReader/ExcelDataReader#332