fix: support function components in _document in no-page-custom-font

[ljosberinn]

• fixes Current eslint rule no-page-custom-font can't handle functional _document #29970

it's now additionally legal to declare a component and then separately export it further down in the file, which was previously a invalid test case despite being perfectly fine syntax and the recommended way of using Custom Document

on a sidenote, the postinstall script fails on Node 17 on Win 11

[housseindjirdeh]

This is great, thank you for doing this @ljosberinn! Just a few minor comments, so once you take a look at them this should be good to go :)

[ijjk]

Stats from current PR

Default Build (Increase detected ⚠️)

General Overall increase ⚠️

	vercel/next.js canary	ljosberinn/next.js fix/eslint-no-page-custom-font	Change
buildDuration	16.9s	17.3s	⚠️ +456ms
buildDurationCached	3.2s	3.2s	⚠️ +8ms
nodeModulesSize	345 MB	345 MB	⚠️ +7 B

Page Load Tests Overall increase ✓

	vercel/next.js canary	ljosberinn/next.js fix/eslint-no-page-custom-font	Change
/ failed reqs	0	0	✓
/ total time (seconds)	2.8	2.971	⚠️ +0.17
/ avg req/sec	892.92	841.6	⚠️ -51.32
/error-in-render failed reqs	0	0	✓
/error-in-render total time (seconds)	1.409	1.338	-0.07
/error-in-render avg req/sec	1774.45	1868.29	+93.84

Client Bundles (main, webpack, commons)

	vercel/next.js canary	ljosberinn/next.js fix/eslint-no-page-custom-font	Change
450.HASH.js gzip	179 B	179 B	✓
framework-HASH.js gzip	42.2 kB	42.2 kB	✓
main-HASH.js gzip	28.4 kB	28.4 kB	✓
webpack-HASH.js gzip	1.45 kB	1.45 kB	✓
Overall change	72.2 kB	72.2 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	ljosberinn/next.js fix/eslint-no-page-custom-font	Change
polyfills-HASH.js gzip	31 kB	31 kB	✓
Overall change	31 kB	31 kB	✓

Client Pages

	vercel/next.js canary	ljosberinn/next.js fix/eslint-no-page-custom-font	Change
_app-HASH.js gzip	1.37 kB	1.37 kB	✓
_error-HASH.js gzip	194 B	194 B	✓
amp-HASH.js gzip	312 B	312 B	✓
css-HASH.js gzip	327 B	327 B	✓
dynamic-HASH.js gzip	2.38 kB	2.38 kB	✓
head-HASH.js gzip	350 B	350 B	✓
hooks-HASH.js gzip	635 B	635 B	✓
image-HASH.js gzip	4.45 kB	4.45 kB	✓
index-HASH.js gzip	263 B	263 B	✓
link-HASH.js gzip	1.87 kB	1.87 kB	✓
routerDirect..HASH.js gzip	321 B	321 B	✓
script-HASH.js gzip	383 B	383 B	✓
withRouter-HASH.js gzip	318 B	318 B	✓
85e02e95b279..7e3.css gzip	107 B	107 B	✓
Overall change	13.3 kB	13.3 kB	✓

Client Build Manifests

	vercel/next.js canary	ljosberinn/next.js fix/eslint-no-page-custom-font	Change
_buildManifest.js gzip	460 B	460 B	✓
Overall change	460 B	460 B	✓

Rendered Page Sizes

	vercel/next.js canary	ljosberinn/next.js fix/eslint-no-page-custom-font	Change
index.html gzip	531 B	531 B	✓
link.html gzip	545 B	545 B	✓
withRouter.html gzip	525 B	525 B	✓
Overall change	1.6 kB	1.6 kB	✓

---

Default Build with SWC (Decrease detected ✓)

General Overall increase ⚠️

	vercel/next.js canary	ljosberinn/next.js fix/eslint-no-page-custom-font	Change
buildDuration	18.6s	18.5s	-112ms
buildDurationCached	3.4s	3.2s	-125ms
nodeModulesSize	345 MB	345 MB	⚠️ +7 B

Page Load Tests Overall decrease ⚠️

	vercel/next.js canary	ljosberinn/next.js fix/eslint-no-page-custom-font	Change
/ failed reqs	0	0	✓
/ total time (seconds)	2.788	2.745	-0.04
/ avg req/sec	896.8	910.91	+14.11
/error-in-render failed reqs	0	0	✓
/error-in-render total time (seconds)	1.325	1.408	⚠️ +0.08
/error-in-render avg req/sec	1887.14	1775.32	⚠️ -111.82

Client Bundles (main, webpack, commons)

	vercel/next.js canary	ljosberinn/next.js fix/eslint-no-page-custom-font	Change
450.HASH.js gzip	179 B	179 B	✓
framework-HASH.js gzip	42.3 kB	42.3 kB	✓
main-HASH.js gzip	28.6 kB	28.6 kB	✓
webpack-HASH.js gzip	1.44 kB	1.44 kB	✓
Overall change	72.5 kB	72.5 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	ljosberinn/next.js fix/eslint-no-page-custom-font	Change
polyfills-HASH.js gzip	31 kB	31 kB	✓
Overall change	31 kB	31 kB	✓

Client Pages

	vercel/next.js canary	ljosberinn/next.js fix/eslint-no-page-custom-font	Change
_app-HASH.js gzip	1.35 kB	1.35 kB	✓
_error-HASH.js gzip	180 B	180 B	✓
amp-HASH.js gzip	305 B	305 B	✓
css-HASH.js gzip	321 B	321 B	✓
dynamic-HASH.js gzip	2.37 kB	2.37 kB	✓
head-HASH.js gzip	342 B	342 B	✓
hooks-HASH.js gzip	622 B	622 B	✓
image-HASH.js gzip	4.47 kB	4.47 kB	✓
index-HASH.js gzip	256 B	256 B	✓
link-HASH.js gzip	1.91 kB	1.91 kB	✓
routerDirect..HASH.js gzip	314 B	314 B	✓
script-HASH.js gzip	375 B	375 B	✓
withRouter-HASH.js gzip	309 B	309 B	✓
85e02e95b279..7e3.css gzip	107 B	107 B	✓
Overall change	13.2 kB	13.2 kB	✓

Client Build Manifests

	vercel/next.js canary	ljosberinn/next.js fix/eslint-no-page-custom-font	Change
_buildManifest.js gzip	458 B	458 B	✓
Overall change	458 B	458 B	✓

Rendered Page Sizes

	vercel/next.js canary	ljosberinn/next.js fix/eslint-no-page-custom-font	Change
index.html gzip	533 B	533 B	✓
link.html gzip	546 B	546 B	✓
withRouter.html gzip	527 B	527 B	✓
Overall change	1.61 kB	1.61 kB	✓

Commit: 4b7bb64

[timneutkens]

Thanks!