Add option to save snippet documentation

[delphidabbler]

Snippet documentation can currently be copied to the clipboard in either plain text or in RTF by using the Edit | Copy Information menu item. But the same information can't be saved to a file.

It would be useful if that could be done.

Furthermore Edit | Copy Information only copies the documentation for the currently selected snippet.

It would be useful if documentation could be output for the current snippet selection OR for the currently selected snippet.

Output in HTML format would be useful too.

Finally, to keep documentation as short as possible, the option to omit source code could be provided.

[delphidabbler]

Finally, to keep documentation as short as possible, the option to omit source code could be provided.

A proposal similar to this for the Edit | Copy Information menu option has been added as separate issue #141.