Writes a PnP spec (#4671)

* Writes a PnP spec

* Formalizes the algorithms

* Updates the PnP header

* Addresses feedbacks from evanw/esbuild#1985

* Starts writing reusable tests

* More tests, clarifications on FIND_PNP_MANIFEST

* Updates style for code segments

* Adds tests for aliases

* Fixes inadvertent default setting change

* Fixes tests

* Versions

Author: arcanis

.pnp.cjs

@@ -0,0 +1,28 @@
+releases:
+  "@yarnpkg/cli": patch
+  "@yarnpkg/pnp": patch
+
+declined:
+  - "@yarnpkg/esbuild-plugin-pnp"
+  - "@yarnpkg/plugin-compat"
+  - "@yarnpkg/plugin-constraints"
+  - "@yarnpkg/plugin-dlx"
+  - "@yarnpkg/plugin-essentials"
+  - "@yarnpkg/plugin-init"
+  - "@yarnpkg/plugin-interactive-tools"
+  - "@yarnpkg/plugin-nm"
+  - "@yarnpkg/plugin-npm-cli"
+  - "@yarnpkg/plugin-pack"
+  - "@yarnpkg/plugin-patch"
+  - "@yarnpkg/plugin-pnp"
+  - "@yarnpkg/plugin-pnpm"
+  - "@yarnpkg/plugin-stage"
+  - "@yarnpkg/plugin-typescript"
+  - "@yarnpkg/plugin-version"
+  - "@yarnpkg/plugin-workspace-tools"
+  - "@yarnpkg/builder"
+  - "@yarnpkg/core"
+  - "@yarnpkg/doctor"
+  - "@yarnpkg/nm"
+  - "@yarnpkg/pnpify"
+  - "@yarnpkg/sdks"