For same reason as we do in Processing registry:
(from the comments included in this commit)
"
While it seems like /Factory/ would be the correct annotations here, that's not
the case.
As per Phil Thomson's advice on https://www.riverbankcomputing.com/pipermail/pyqt/2017-July/039450.html:
"
/Factory/ is used when the instance returned is guaranteed to be new to Python.
In this case it isn't because it has already been seen when being returned by QgsProcessingAlgorithm::createInstance()
(However for a different sub-class implemented in C++ then it would be the first time it was seen
by Python so the /Factory/ on create() would be correct.)
You might try using /TransferBack/ on create() instead - that might be the best compromise.
"
Allows for creation of tables with contents manually entered by users
(i.e. spreadsheet style), so that users can create completely custom
tables.
Supports control custom cell contents, foreground and background colors.
For the c++ api dox this expands to "\c nullptr" (the
\c directive indicates a code literal value), and for sipify/Python
it expands to ``None`` (`` is sphinx annotation for literal values)
Makes for nicer dox for both c++ and Python!
