fix: read the docs the same on a CRLF checkout

[Dusk1e]

Problem

npm run test fails on main for anyone whose git checked out CRLF, which is the default on Windows:

1) public exports
     finds the docs it is supposed to read:
     named imports of @opensea/seaport-js in README code fences

The fence pattern is anchored on a newline:

const fence = /```[a-zA-Z]*\n([\s\S]*?)```/g

So it never matches ```js\r\n, and the README scan comes back empty. Converting README.md to LF and rerunning the same commit turns it green again, which is why CI has not seen this — it checks out LF.

The vacuity guard is what caught it, and it caught exactly what it was put there for. Without it the run would have been green while reading nothing: exports every symbol the README's code examples import and exports every helper a doc comment promises is exposed both filter a list and compare against [], so an empty input satisfies them. On a CRLF clone those two checks were passing without looking at anything.

Fix

Normalise line endings where the files are read, so every scan sees the same text whatever the checkout did.

importedSymbolsIn normalises its own argument too. That is not redundancy for its own sake — it makes the parse independent of how the caller obtained the text, which is what lets it be driven directly from a test.

Test

One case, feeding the same fence through both line endings and expecting the same symbol out of each. It does not read from disk, so it holds regardless of what the checkout did, and a CI run on LF catches a regression here as well.

On a CRLF checkout this suite goes from one failure to none; the full run is 244.