[Patch] Fix for TryStrToConvUnit in ConvUtils unit
Attached patch fixes TryStrToConvUnit.
Some remarks though:
- The new algorithm is based on the single example that is given in the Delphi docs. It is not tested against Delphi behaviour (simply because my D7 does not implement this function)
- Even while the new behaviour may differ from Delphi (I don't know), the new behaviour is correct because there are no constraints on the description of a registered TConvType, so it may be an empty string, have leading or trailing spaces, or consists of only spaces.
- Given the single example in the Delphi docs, we can then deduce that "Value" and "Description" must be separated by exactly one single space in order for the AText parameter to be valid.
- The patch also fixes a poetentiol RangeCheck error.