Please allow disabling WYSIWYG editor

WYSIWYG is a disaster: I can't write meaningful descriptions to pull requests or comments to commits. I can't paste code in code blocks - text is pasted after the block, it seems cant work with two or code blocks - the first one is not formatted a expected (code block), etc. I can't paste texts without automatic (and odd) formatting.

WYSIWYG might be a good thing for non-programmers, but Bitbucket is not Wikipedia.

Also see the attachment.