fix: don't escape dash in define regex

[jonaskuske]

Description

fix #9964

Additional context

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What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

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[patak-dev]

As you explained in #9964 (comment), the define feature needs to work both during build and dev. So we can't allow dashes if they are only going to work during build. I think your recommendations in #9964 were on point, and we should keep define as is.

[jonaskuske]

👍🏻👍🏻

I still think that constructing an invalid Regex isn't really sound though. What do you think about fixing the Regex so it doesn't throw an obscure error anymore, but printing a warning if a define key contains a character that can't be part of a variable/identifier?

[patak-dev]

@jonaskuske that sounds like a great improvement 👍🏼

[sapphi-red]

Given that we now use esbuild for define (#11151), I guess this is no longer needed.