Allow month names in StrToDate and StrToDateTime

[CudaText-addons]

Quote from the Lazarus issue tracker. Please also support this in Delphi.

Motivated by freepascal.org/lazarus/lazarus#39779 (closed) I thought about the issue that StrToDate and StrToDateTime allow only numeric values in their date/time parts. The format expected is taken from the ShortDateFormat of the FormatSettings record where the month is assumed to be in the one- or two-digit representation.

But why can there be only numbers in the month part? In the FormatSettings.ShortDateFormat the month can be specified as 'mmm' or even 'mmmm' - and this inserts the short or long month names in the strings created by DateToStr. However, these strings cannot be converted back to dates by calling the inverse StrToDate function? I know that Delphi does the same, it accepts only numeric month strings. But I don't see a real reason for this asymmetry.