Fix wrong language scope in markdown inline math expression

[robincaloudis]

Why

In #148644, it was shown
that given a markdown inline math with $$
when the cursor position is directly in front
of the closing dollar symbol then that the language
scope shows markdown instead of the language
scope latex.

What

Previously, the first and third group was
defined as beginning. This is not
true as the first group of the regular
expression is the beginning of the math
inline markdown expression and the third
group the end. Once the third group is
correctly assigned, its language scope can
be changed accordingly.

Fixes #148644

[robincaloudis]

@microsoft-github-policy-service agree

[robincaloudis]

Hello @Tyriar and @mjbvz, thanks for the review! How do I get a successful check on revent yarn.lock changes in PRs? Currently, it is not reported and marked as Expected — Waiting for status to be reported

[robincaloudis]

Hi again @Tyriar and @mjbvz, could you tell me why I still see Merging is blocked - Merging can be performed automatically with 1 approving review. even though both of you have approved? Do you have to re-approve as I merged the branch main into my branch? Best, Robin