patch 9.1.1893: ICCF charity will dissolve

patch 9.1.1893: ICCF charity will dissolve

Problem:  ICCF charity will dissolve
Solution: Update references to Kuwasha

Since the ICCF[1] will be dissolved and handing over to the Kuwasha charity
to continue supporting the Kibaale Children Center in Uganda, update the
uganda.txt help file.

[1]: https://groups.google.com/g/vim_announce/c/pUNbNXBLbKw/m/-zFUd4JjAQAJ

fixes: #18584
closes: #18667

Signed-off-by:
Signed-off-by: Christian Brabandt <cb@256bit.org>