Writes or updates the named FITS keyword record with the given string value.
Plate.WriteFITSString(Keyword, Value)
The method syntax has these parts:
| Part | Description | 
|---|---|
| Keyword (String) | The keyword to write or update | 
| Value (String) | The new string value for the keyword. | 
| Return (Boolean) | Success or failure (generates trappable error on failure) |