BlSHRBTextStyler may style out-of-bounds intervals during incremental editing

[badetitou]

I did not find a way to reproduce the issue programmatically without Toplo, but when coding, or updating some code panel, we sometimes have this issue

It looks like updating method addAttributes: attributes from: start to: stop to

addAttributes: attributes from: start to: stop

	| actualStart actualStop subText |
	actualStart := start max: 1.
	actualStop := stop min: blocText size.
	actualStart <= actualStop ifFalse: [ ^ self ].

	subText := blocText from: actualStart to: actualStop.
	attributes do: [ :each | each applyToBlText: subText ]

Can fix the issue, but it looks like a hotfix to me and we need to investigate more the bug reason

[tinchodias]

Mmm let's apply your fix for now. Could you post a PR pleasE?