fix(maybeInstallable): match TERMS_EXTS_NON_BUILD against filename, not URL

[coolaj86]

Summary

Fix a false-positive in Triplet.maybeInstallable that drops package versions ending in .1 when the download URL is a GitHub source-archive endpoint.

Bug

maybeInstallable checks each entry in TERMS_EXTS_NON_BUILD (which includes .1 for matching man-page section-1 files like mytool.1) against the full build.download URL:

for (let ext of Triplet.TERMS_EXTS_NON_BUILD) {
    if (build.download.endsWith(ext)) {
        return false;
    }
}

For packages that publish only as GitHub source archives, the download URL is the API endpoint:

https://api.github.com/repos/bnnanet/serviceman/tarball/v1.0.1
                                                          ^^
                                                  ends with ".1"

maybeInstallable returns false, _classify silently returns null, and transformAndUpdate's "ignore known, non-package extensions" path drops the build with no error message. The package's newest release becomes invisible to the resolver.

Repro

let T = require('./triplet.js');
let v101 = {
    name: 'serviceman-v1.0.1.tar.gz',
    version: '1.0.1',
    ext: 'tar.gz',
    download: 'https://api.github.com/repos/bnnanet/serviceman/tarball/v1.0.1',
};
T.maybeInstallable({ name: 'serviceman' }, v101);
// before: false   ← bug
// after:  true

Fix

Check build.name (the canonical filename) instead of build.download. The filename for serviceman-v1.0.1.tar.gz ends in .tar.gz, not .1. Real .1 man-page files have .1 in their name too, so detection of those is unaffected. Same change applied to the _RE_TERMS_NON_BUILD loop for consistency.

Test plan

• Unit verification (in commit message body):
  • serviceman-v1.0.1.tar.gz → true (was false)
  • serviceman-v1.0.0.tar.gz → true (unchanged)
  • mytool.1 (manpage) → false (unchanged)
• Run webicached + webi serviceman end-to-end and confirm v1.0.1 (or whatever the newest patch.1 version is) resolves to the tarball, not v1.0.0.
• Confirm no regression in other packages — particularly any that publish actual .1/.deb/.rpm/etc. files.

Impact

Affects any package whose version ends in .1 and whose download URL is a GitHub source-archive endpoint (/tarball/vX.Y.1 or /zipball/vX.Y.1). Observed in the wild for serviceman v1.0.1 (patch releases generally), aliasman, and the source-only vim plugins.

Surfaced while validating PR #1074 in webinstall/webi-installers — the resolver was returning v1.0.0 instead of v1.0.1 for serviceman, which traced back to this classifier rejection.