more explained error code for name-less umd bundle

[rail44]

This PR contains:

• bugfix
• feature
• refactor
• documentation
• other

Are tests included?

• yes (bugfixes and features will not be merged without tests)
• no

Breaking Changes?

• yes (breaking changes will not be merged unless absolutely necessary)
• no

List any relevant issue numbers:

Description

refs #3372

In above PR, I was suggested to tweak error code for UMD bundle.
Because this patch will be breaking change for people already using this code in plugins, I create PR based on release-2.0.0 .

[shellscape]

Not in favor of this change. It's still too vague in the larger context of Rollup, and if we're going to make a breaking change then a clear, concise, explanatory error code should be chosen.

[lukastaegert]

@shellscape What would be your suggestion? For me, the important part is that it should be aligned with the same error code for IIFE which is added in #3372. The error is that the name option was not used even though the bundle has exports, so MISSING_NAME_FOR_EXPORT is not too far off, considering there is also the prose error message. These codes are mainly to enable filtering errors and warnings without relying on matching error messages. We could extend it slightly to MISSING_NAME_OPTION_FOR_EXPORT or MISSING_NAME_OPTION_FOR_IIFE_EXPORT to emphasize that this is solely about the IIFE part of the UMD output that does not work. Opinions?

[lukastaegert]

I have changed the error code as suggested by me and also further extended the error message to explain why we need a name at all (and we have an IIFE error for UMD bundles). @shellscape would this work for you so that we can proceed here?

[codecov]

Codecov Report

Merging #3393 into release-2.0.0 will not change coverage.
The diff coverage is n/a.

@@              Coverage Diff              @@
##           release-2.0.0   #3393   +/-   ##
=============================================
  Coverage             95%     95%           
=============================================
  Files                171     171           
  Lines               5801    5801           
  Branches            1712    1712           
=============================================
  Hits                5511    5511           
  Misses               157     157           
  Partials             133     133

Impacted Files	Coverage Δ
src/finalisers/umd.ts	94.91% <ø> (ø)	⬆️

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