Instead of using innerText, this now uses the getTextContentsOfRange
helper fn to work out the white space, so is consistent with the
editor's getSelectedText method and should be higher fidelity.
Note, you can still override the behaviour by supplying a toPlainText
fn in the editor config (such as the one you can find at
https://github.com/fastmail/overture/blob/master/source/html/toPlainText.js)
This is a massive refactor to port Squire to TypeScript, fix a bunch of small
bugs and modernise our tooling. The development was done on an internal
repository, so apologies to anyone following externally for the commit dump;
updates from here should come as real commits again.
Co-authored-by: Joe Woods <woods@fastmailteam.com>
