mime: extend "builtinTypes" to include a more complete list of common types

[AidanWelch]

Simply implements the first recommended type for each file extension listed
in MDN
https://developer.mozilla.org/en-US/docs/Web/HTTP/Basics_of_HTTP/MIME_types/Common_types

However, this excludes ".3gp" and ".3gp2" as from from I can tell it is not
possible to know if it is video or audio solely from file extension.

As far as I can tell there are at least two previous PRs that each
implemented a type simply because they were in common use, this would try
to implement a more expansive list rather than piecemeal implementations.

Updates #69530

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Patch Set 1:

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Message from Aidan Welch:

Patch Set 2:

(1 comment)

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Message from Ian Lance Taylor:

Patch Set 2:

(2 comments)

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Message from Ian Lance Taylor:

Patch Set 2: Hold+1

(1 comment)

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Message from Aidan Welch:

Patch Set 2:

(1 comment)

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