Update `krita_manual_readme.rst` to remove instruction to create `webchat.kde.org` account.
requested to merge rokejulianlockhart/docs-krita-org:rokejulianlockhart-master-patch-26026 into master
Remediates https://krita-artists.org/t/how-to-create-an-account-on-webchat-kde-org/42333/4?u=rokejulianlockhart by not contradicting official documentation:
While registrations on the KDE Matrix homeserver are closed, you can register on any Matrix homeserver and you will be able to talk to anyone using Matrix.