fix: Intra-word emphasis can match the wrong asterisks

[Scrum]

Description

• Fixes Intra-word emphasis can match the wrong asterisks, issue Intra-word emphasis can match the wrong asterisks #1607

Contributor

• Test(s) exist to ensure functionality and minimize regression (if no tests added, list tests covering this PR)

Committer

In most cases, this should be a different person than the contributor.

• Draft GitHub release notes have been updated.
• CI is green (no forced merge required).
• Merge PR

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[UziTech]

@davisjam could you check if the new regex is vulnerable to ReDos?

[Scrum]

@UziTech @davisjam ping ?

[UziTech]

It doesn't looks like this changes the structure of the regex so if it wasn't vulnerable before than it shouldn't be now.

Good work! 💯

[styfle]

Thanks!