[manusingh090]

The "exports" field definition lists string[] as an accepted type, but
packages.md never explains how an array of targets is resolved. This has
led people to assume an array falls back to the next file when the first
one does not exist (see the linked issue), which is not what happens.

This adds a "Target fallback arrays" section after "Nested conditions"
that documents:

• an array can be used anywhere a target is accepted, in both "exports"
  and "imports", and items are tried in order;
• an item is skipped only if it is an invalid target or a conditions
  object with no matching condition;
• file existence is not checked, so a valid first target that points to a
  missing file fails instead of falling through to the next item;
• an empty array means the subpath is not exported, and if every item is
  invalid the last error is thrown.

The wording follows PACKAGE_TARGET_RESOLVE in esm.md and
resolvePackageTarget() in lib/internal/modules/esm/resolve.js.

Verification

Tested with a small package in node_modules on Node.js ,
using both require() and import():

exports target	Result
["./nope.js", "./b.js"]	module not found
["../outside.js", "./b.js"]	loads ./b.js
[{ "browser": "./nope.js" }, "./b.js"]	loads ./b.js
[]	ERR_PACKAGE_PATH_NOT_EXPORTED
["../x.js", "../y.js"]	ERR_INVALID_PACKAGE_TARGET

node tools/lint-md/lint-md.mjs doc/api/packages.md passes.

AI disclosure

I used an AI coding assistant to help read the resolver code and draft the
text. I reviewed the section against the resolver source and ran the tests
above myself.

Fixes: #58600

[nodejs-github-bot]

Review requested:

• @nodejs/loaders

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[ljharb]

LGTM