Function toHyperlinkAddress

toHyperlinkAddress(text: string): string | null
The hyperlink address for text that Excel's AutoCorrect would turn into a link, or null when the text is not link-shaped.
Parameters
- text: string
  The text to check.
Returns string | null
The address, with the scheme Excel supplies when the text omits one, or null.
Remarks
Mirrors Excel's "Internet and network paths with hyperlinks" rule, which links:
- http(s)://… - as is.
- www.… - as http://www.….
- mailto:… - as is.
- an email address - as mailto:….
A bare domain (sheetxl.com) is left alone, as Excel leaves it.