Ensure @rematch and nextEmbedded can be used together in Monarch grammar

[bolinfest]

Similar to the repro case I created for #90266, I created a local
playground with the following:

const DEMO_LANG_ID = "demo";
const SQL_QUERY_START = "(SELECT|INSERT|UPDATE|DELETE|CREATE|REPLACE|ALTER|WITH)";

const languageConfiguration = {
	tokenizer: {
		root: [
			[
				`(\"\"\")${SQL_QUERY_START}`,
				[
					{
						"token": "string.quote",
					},
					{
						token: "@rematch",
						next: "@endStringWithSQL",
						nextEmbedded: "sql",
					},
				]
			],
			[
				/(""")$/,
				[
					{
						token: "string.quote",
						next: "@maybeStringIsSQL",
					},
				]
			],
		],
		maybeStringIsSQL: [
			[
				/(.*)/,
				{
					cases: {
						[`${SQL_QUERY_START}\\b.*`]: {
							token: "@rematch",
							next: "@endStringWithSQL",
							nextEmbedded: "sql",
						},
						"@default": {
							token: "@rematch",
							switchTo: "@endDblDocString",
						},
					}
				}
			],
		],
		endDblDocString: [
			[
				"[^\"]+",
				"string"
			],
			[
				"\\\\\"",
				"string"
			],
			[
				"\"\"\"",
				"string",
				"@popall"
			],
			[
				"\"",
				"string"
			]
		],
		endStringWithSQL: [
			[
				/"""/,
				{
					token: "string.quote",
					next: "@popall",
					nextEmbedded: "@pop",
				},
			]
		],
	},
};
monaco.languages.register({
	id: DEMO_LANG_ID,
	extensions: ['.example'],
});
monaco.languages.setMonarchTokensProvider(DEMO_LANG_ID, languageConfiguration);

const value = `\
mysql_query("""SELECT * FROM table_name WHERE ds = '<DATEID>'""")

mysql_query("""
SELECT *
FROM table_name
WHERE ds = '<DATEID>'
""")
`;

var editor = monaco.editor.create(document.getElementById("container"), {
	value,
	language: DEMO_LANG_ID,

	lineNumbers: "off",
	roundedSelection: false,
	scrollBeyondLastLine: false,
	readOnly: false,
	theme: "vs-dark",
});

Without my change to monarchLexer.ts, I get this error in the console:

errors.ts:26 Uncaught Error: demo: cannot pop embedded mode if not inside one

But with my change, I see a Python-esque multiline string literal with
SQL syntax highlighting within it.

[msftclas]

All CLA requirements met.

[bolinfest]

/cc @alexdima

[alexdima]

Thank you!