gh-35866: CI build.yml, doc-build.yml: Use output groups
    
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### 📚 Description

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With this change, the output of each spkg build is put in foldable
output groups.

The output synchronization is not perfect, but it's still much better
than before.

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URL: #35866
Reported by: Matthias Köppe
Reviewer(s): Kwankyu Lee, Matthias Köppe, Tobias Diez

Author: Release Manager

.github/workflows/build.yml

@@ -76,15 +76,15 @@ jobs:
           ./bootstrap && make build && ./sage -t --new -p2
         working-directory: ./worktree-image
         env:
-          MAKE: make -j2
+          MAKE: make -j2 --output-sync=recurse
           SAGE_NUM_THREADS: 2
 
       - name: Build and test modularized distributions
         if: always() && steps.worktree.outcome == 'success'
         run: make V=0 tox && make pypi-wheels
         working-directory: ./worktree-image
         env:
-          MAKE: make -j2
+          MAKE: make -j2 --output-sync=recurse
           SAGE_NUM_THREADS: 2
 
       - name: Set up node to install pyright
@@ -123,7 +123,7 @@ jobs:
           make build
         working-directory: ./worktree-image
         env:
-          MAKE: make -j2
+          MAKE: make -j2 --output-sync=recurse
           SAGE_NUM_THREADS: 2
 
       - name: Pytest

.github/workflows/doc-build.yml

@@ -61,7 +61,7 @@ jobs:
           ./bootstrap && make build
         working-directory: ./worktree-image
         env:
-          MAKE: make -j2
+          MAKE: make -j2 --output-sync=recurse
           SAGE_NUM_THREADS: 2
 
       - name: Build (fallback to non-incremental)
@@ -72,7 +72,7 @@ jobs:
           make doc-clean doc-uninstall sagelib-clean && git clean -fx src/sage && ./config.status && make build
         working-directory: ./worktree-image
         env:
-          MAKE: make -j2
+          MAKE: make -j2 --output-sync=recurse
           SAGE_NUM_THREADS: 2
 
       - name: Build docs
@@ -89,7 +89,7 @@ jobs:
           ./config.status && make doc-html
         working-directory: ./worktree-image
         env:
-          MAKE: make -j2
+          MAKE: make -j2 --output-sync=recurse
           SAGE_NUM_THREADS: 2
 
       - name: Copy docs

build/bin/sage-logger

@@ -89,8 +89,9 @@ else
     # Redirect stdout and stderr to a subprocess running tee.
     # We trap SIGINT such that SIGINT interrupts the main process being
     # run, not the logging.
+
     ( exec 2>&1; eval "$cmd" ) | \
-        ( trap '' SIGINT; tee -a "$logfile" | $SED )
+        ( trap '' SIGINT; if [ -n "$GITHUB_ACTIONS" -a -n "$prefix" ]; then echo "::group::${logname}"; fi; tee -a "$logfile" | $SED; if [ -n "$GITHUB_ACTIONS" -a -n "$prefix" ]; then echo "::endgroup::"; fi )
 
     pipestatus=(${PIPESTATUS[*]})