feat: support custom dts transpiler

[jbedard]

Support a custom transpiler for producing dts files.

Overview of targets created:

• {name} outputs a JsInfo containing all transpiled files, no guarantee if this runs tsc, no guarantee it outputs anything such as no_emit = True

If any transpiler or no_emit is used then the following are also created:

• {name}_types if declaration: True && not no_emit: dts files in DefaultInfo
• {name}_tsc invokes tsc, maybe outputting something, maybe doing type-checking, maybe both
• {name}_typecheck outputs something when type-checking passes
• {name}_typecheck_test forces {name}_typecheck to build and therefor forces type-checking

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Changes are visible to end-users: yes

• Searched for relevant documentation and updated as needed: yes
• Breaking change (forces users to change their own code or config): no
• Suggested release notes appear below: yes

A custom dts transpiler can now be set using ts_project(declaration_transpiler). This aligns dts transpiling with js transpiling allowing fast transpiling of all files, only requiring invoking tsc for a type-checking action.

Test plan

• Covered by existing test cases
• New test cases added

[aspect-workflows]

Test

1 test target passed

Targets

//docs:update_0_test [k8-fastbuild] 25ms

Total test execution time was 25ms. 103 tests (99.0%) were fully cached saving 9s.

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Buildifier      Format

[jbedard]

TODO: tests, I think swc isn't ready (swc-project/swc#9512) so we might have to try something else, even just a js_binary hiding plain old tsc

[MichaelMitchell-at]

I tested this out on our repo and I ran into some issues. I think if my comments are addressed we'll be good though!

[MichaelMitchell-at]

Tested it out on our code base. Works great!

[jbedard]

Updated. See the outline of targets I put into the PR description.

IMO the {name}_types target should always be created, even if we are using tsc for everything (js + dts) this {name}_types target extracts the dts files into DefaultInfo. I don't see any reason why that should only be set when using a transpiler?