Add .jsx as a valid file extension in the pages directory

[bartdeslagmulder]

It's possible to use a .jsx file extension in the pages directory but the doc doesn't mention it.
Next to the current extensions: .js, .ts & .tsx I would mention .jsx also in the list.

[ijjk]

Stats from current PR

Default Server Mode

General

	zeit/next.js canary	bartdeslagmulder/next.js patch-1	Change
buildDuration	13s	12.6s	-373ms
nodeModulesSize	52.1 MB	52.1 MB	✓

Client Bundles (main, webpack, commons)

	zeit/next.js canary	bartdeslagmulder/next.js patch-1	Change
main-HASH.js gzip	5.1 kB	5.1 kB	✓
webpack-HASH.js gzip	746 B	746 B	✓
4952ddcd88e7..54d3.js gzip	4.68 kB	4.68 kB	✓
commons.HASH.js gzip	4.06 kB	4.06 kB	✓
de003c3a9d30..d57b.js gzip	16.1 kB	16.1 kB	✓
framework.HASH.js gzip	39.1 kB	39.1 kB	✓
Overall change	69.8 kB	69.8 kB	✓

Client Bundles (main, webpack, commons) Modern

	zeit/next.js canary	bartdeslagmulder/next.js patch-1	Change
main-HASH.module.js gzip	4.09 kB	4.09 kB	✓
webpack-HASH..dule.js gzip	746 B	746 B	✓
4952ddcd88e7..dule.js gzip	5.56 kB	5.56 kB	✓
de003c3a9d30..dule.js gzip	15 kB	15 kB	✓
framework.HA..dule.js gzip	39.1 kB	39.1 kB	✓
Overall change	64.5 kB	64.5 kB	✓

Legacy Client Bundles (polyfills)

	zeit/next.js canary	bartdeslagmulder/next.js patch-1	Change
polyfills-HASH.js gzip	4.76 kB	4.76 kB	✓
Overall change	4.76 kB	4.76 kB	✓

Client Pages

	zeit/next.js canary	bartdeslagmulder/next.js patch-1	Change
_app.js gzip	1.15 kB	1.15 kB	✓
_error.js gzip	4.07 kB	4.07 kB	✓
hooks.js gzip	779 B	779 B	✓
index.js gzip	222 B	222 B	✓
link.js gzip	2.89 kB	2.89 kB	✓
routerDirect.js gzip	283 B	283 B	✓
withRouter.js gzip	282 B	282 B	✓
Overall change	9.68 kB	9.68 kB	✓

Client Pages Modern

	zeit/next.js canary	bartdeslagmulder/next.js patch-1	Change
_app.module.js gzip	576 B	576 B	✓
_error.module.js gzip	3.06 kB	3.06 kB	✓
hooks.module.js gzip	371 B	371 B	✓
index.module.js gzip	212 B	212 B	✓
link.module.js gzip	2.46 kB	2.46 kB	✓
routerDirect..dule.js gzip	273 B	273 B	✓
withRouter.m..dule.js gzip	272 B	272 B	✓
Overall change	7.22 kB	7.22 kB	✓

Client Build Manifests

	zeit/next.js canary	bartdeslagmulder/next.js patch-1	Change
_buildManifest.js gzip	61 B	61 B	✓
_buildManife..dule.js gzip	61 B	61 B	✓
Overall change	122 B	122 B	✓

Rendered Page Sizes

	zeit/next.js canary	bartdeslagmulder/next.js patch-1	Change
index.html gzip	1.02 kB	1.02 kB	✓
link.html gzip	1.03 kB	1.03 kB	✓
withRouter.html gzip	1.02 kB	1.02 kB	✓
Overall change	3.07 kB	3.07 kB	✓

---

Serverless Mode

General

	zeit/next.js canary	bartdeslagmulder/next.js patch-1	Change
buildDuration	13.3s	13.1s	-202ms
nodeModulesSize	52.1 MB	52.1 MB	✓

Client Bundles (main, webpack, commons)

	zeit/next.js canary	bartdeslagmulder/next.js patch-1	Change
main-HASH.js gzip	5.1 kB	5.1 kB	✓
webpack-HASH.js gzip	746 B	746 B	✓
4952ddcd88e7..54d3.js gzip	4.68 kB	4.68 kB	✓
commons.HASH.js gzip	4.06 kB	4.06 kB	✓
de003c3a9d30..d57b.js gzip	16.1 kB	16.1 kB	✓
framework.HASH.js gzip	39.1 kB	39.1 kB	✓
Overall change	69.8 kB	69.8 kB	✓

Client Bundles (main, webpack, commons) Modern

	zeit/next.js canary	bartdeslagmulder/next.js patch-1	Change
main-HASH.module.js gzip	4.09 kB	4.09 kB	✓
webpack-HASH..dule.js gzip	746 B	746 B	✓
4952ddcd88e7..dule.js gzip	5.56 kB	5.56 kB	✓
de003c3a9d30..dule.js gzip	15 kB	15 kB	✓
framework.HA..dule.js gzip	39.1 kB	39.1 kB	✓
Overall change	64.5 kB	64.5 kB	✓

Legacy Client Bundles (polyfills)

	zeit/next.js canary	bartdeslagmulder/next.js patch-1	Change
polyfills-HASH.js gzip	4.76 kB	4.76 kB	✓
Overall change	4.76 kB	4.76 kB	✓

Client Pages

	zeit/next.js canary	bartdeslagmulder/next.js patch-1	Change
_app.js gzip	1.15 kB	1.15 kB	✓
_error.js gzip	4.07 kB	4.07 kB	✓
hooks.js gzip	779 B	779 B	✓
index.js gzip	222 B	222 B	✓
link.js gzip	2.89 kB	2.89 kB	✓
routerDirect.js gzip	283 B	283 B	✓
withRouter.js gzip	282 B	282 B	✓
Overall change	9.68 kB	9.68 kB	✓

Client Pages Modern

	zeit/next.js canary	bartdeslagmulder/next.js patch-1	Change
_app.module.js gzip	576 B	576 B	✓
_error.module.js gzip	3.06 kB	3.06 kB	✓
hooks.module.js gzip	371 B	371 B	✓
index.module.js gzip	212 B	212 B	✓
link.module.js gzip	2.46 kB	2.46 kB	✓
routerDirect..dule.js gzip	273 B	273 B	✓
withRouter.m..dule.js gzip	272 B	272 B	✓
Overall change	7.22 kB	7.22 kB	✓

Client Build Manifests

	zeit/next.js canary	bartdeslagmulder/next.js patch-1	Change
_buildManifest.js gzip	61 B	61 B	✓
_buildManife..dule.js gzip	61 B	61 B	✓
Overall change	122 B	122 B	✓

Serverless bundles

	zeit/next.js canary	bartdeslagmulder/next.js patch-1	Change
_error.js gzip	46.2 kB	46.2 kB	✓
hooks.html gzip	1.06 kB	1.06 kB	✓
index.js gzip	46.4 kB	46.4 kB	✓
link.js gzip	71.9 kB	71.9 kB	✓
routerDirect.js gzip	69.9 kB	69.9 kB	✓
withRouter.js gzip	69.9 kB	69.9 kB	✓
Overall change	305 kB	305 kB	✓

Commit: 3697360

[timneutkens]

Thanks!