[Bug] The setMonarchTokensProvider rule matches incorrectly

Reproducible in vscode.dev or in VS Code Desktop?

• Not reproducible in vscode.dev or VS Code Desktop

Reproducible in the monaco editor playground?

https://microsoft.github.io/monaco-editor/playground.html?source=v0.47.0#XQAAAAJ3AgAAAAAAAABBqQkHQ5NjdMjwa-jY7SIQ9S7DNlzs5W-mwj0fe1ZCDRFc9ws9XQE0SJE1jc2VKxhaLFIw9vEWSxW3yscw15yhqT9RSPWJrMzrzzSucLOyj4KniHiZKetJN83iKCIna1cjwLSQRb-627e2KFeF76IibMJYXcyCAabseBrQkTTa5u03nxl7PDMek0QnoWEHXoFGAxHI7185bCqcVeGupMoN1QDNfNSR246VtJ4QRWEJxFU0o-uhd7n3nPv1k5LD3MMBeurNiqRkFmSUdzo7Zm2ctJApX0uxBtviaIB6s5RC7yguN5eLYnP7Gw_bXMpK-nK1MJqu168K-xMo5DtZv2cwEhTPmGIwXuB8JRYUatJ1IMkGLuT3NHJocARPGJK5S-AankYTobQARTCNLxbvoql1HvId9zgLeM9iYJ1AhotMnIQdwooQSMdC3z3UkFfhCGuoBaM7SUeABEdc3YPRoFQs0fn6rBxu8dKYQeHNECecVsKgnaDQjn_qgswN1z5-IOlYTNM1_vWDZaA

Monaco Editor Playground Link

I have a list of rules

const keywords = [Stop,.............]
  monaco?.languages.setMonarchTokensProvider('cpp', {
      tokenizer: {
        root: [[new RegExp(`\\b(${keywords.join('|')})\\b`), 'keyword']]
      },
      keywords: [Stop,.............]
    });

I expected all keywords to be highlighted, but now Stop is included in the keywords list, but words ending in Stop will still be highlighted

The effect at the beginning of Stop is correct, but the effect at the end of Stop is wrong and should be shown in black, not yellow

How do I make it highlighted as a keyword only for Stop words, it shouldn't be highlighted if there are letters or words before and after it

Monaco Editor Playground Code

monaco.languages.register({ id: "mySpecialLanguage" });

monaco.languages.setMonarchTokensProvider("mySpecialLanguage", {
	tokenizer: {
		root: [
      		[/(?<!\w)Stop(?!\w)/, 'keyword']
		],
	},
});

monaco.editor.defineTheme("myCoolTheme", {
	base: "vs",
	inherit: false,
	rules: [
		{ token: 'keyword', foreground: 'f1d710' },
	],
	colors: {
		"editor.foreground": "#000000",
	},
});


monaco.editor.create(document.getElementById("container"), {
	theme: "myCoolTheme",
	value: `Stop
QdStop
qdStop
11Stop
StopSS
Stop11
Stopdd 
	`,
	language: "mySpecialLanguage",
});

Reproduction Steps

No response

Actual (Problematic) Behavior

No response

Expected Behavior

No response

Additional Context

No response

Start with the linked Monaco Editor Playground reproduction and the setMonarchTokensProvider tokenizer rule using the Stop regex. Verify how token boundaries behave for Stop, QdStop, StopSS, and similar values; done means only the standalone Stop token is highlighted as a keyword.