chore: enable build-specific documentation roots (#7455)

This PR enables the use of the build-time configuration of the Lean
reference manual URL and updates the release checklist to account for
the reference manual.

This is a follow-up to #7240, after the required `stage0` update.

The release process described here uses the same location for the
reference manual for RCs and stable releases. This is for two reasons:
1. The only changes between them should be a modification of the
embedded version string and updates to the final release's release
notes, once those are included.
2. It ensures that a compatible manual is available at the moment that
the new release appears, so any delay getting it deployed won't be
visible to users.

doc/dev/release_checklist.md

@@ -13,7 +13,8 @@ We'll use `v4.6.0` as the intended release version as a running example.
 - In `src/CMakeLists.txt`, verify you see
   - `set(LEAN_VERSION_MINOR 6)` (for whichever `6` is appropriate)
   - `set(LEAN_VERSION_IS_RELEASE 1)`
-  - (both of these should already be in place from the release candidates)
+  - (all of these should already be in place from the release candidates)
+
 - `git tag v4.6.0`
 - `git push $REMOTE v4.6.0`, where `$REMOTE` is the upstream Lean repository (e.g., `origin`, `upstream`)
 - Now wait, while CI runs.
@@ -80,6 +81,11 @@ We'll use `v4.6.0` as the intended release version as a running example.
       - Toolchain bump PR including updated Lake manifest
       - Create and push the tag
       - There is no `stable` branch; skip this step
+    - [Reference Manual](https://github.com/leanprover/reference-manual)
+      - Dependencies: Verso
+      - Toolchain bump PR including updated Lake manifest
+      - Pushing the tag (whether for an RC or a final) triggers a deployment.
+      - There is no `stable` branch; skip this step
     - [Cli](https://github.com/leanprover/lean4-cli)
       - No dependencies
       - Toolchain bump PR
@@ -169,6 +175,7 @@ We'll use `v4.7.0-rc1` as the intended release version in this example.
 - `git tag v4.7.0-rc1`
 - `git push origin v4.7.0-rc1`
 - Now wait, while CI runs.
+  - The CI setup parses the tag to discover the `-rc1` special description, and passes it to `cmake` using a `-D` option. The `-rc1` doesn't need to be placed in the configuration file.
   - You can monitor this at `https://github.com/leanprover/lean4/actions/workflows/ci.yml`, looking for the `v4.7.0-rc1` tag.
   - This step can take up to an hour.
 - (GitHub release notes) Once the release appears at https://github.com/leanprover/lean4/releases/

src/CMakeLists.txt

@@ -20,6 +20,11 @@ if (LEAN_SPECIAL_VERSION_DESC)
 elseif (NOT LEAN_VERSION_IS_RELEASE)
   string(APPEND LEAN_VERSION_STRING "-pre")
 endif()
+if (LEAN_VERSION_IS_RELEASE)
+  set(LEAN_MANUAL_ROOT "https://lean-lang.org/doc/reference/${LEAN_VERSION_STRING}/")
+else()
+  set(LEAN_MANUAL_ROOT "")
+endif()
 
 set(LEAN_PLATFORM_TARGET "" CACHE STRING "LLVM triple of the target platform")
 if (NOT LEAN_PLATFORM_TARGET)

src/Lean/DocString/Links.lean

@@ -11,11 +11,8 @@ set_option linter.missingDocs true
 
 namespace Lean
 
-/- After a stage0 update:
-@[extern "lean_get_manual_root"]
+@[extern "lean_manual_get_root"]
 private opaque getManualRoot : Unit → String
--/
-private def getManualRoot : Unit → String := fun () => ""
 
 private def fallbackManualRoot := "https://lean-lang.org/doc/reference/latest/"