Document b2 parameters (#1332)

There was no clear description of what the `b2` parameters did.

[Related
discussion](#1322 (comment)).

Author: JackPGreen

.github/actions/build-test/windows/action.yml

@@ -91,6 +91,10 @@ runs:
         rm ${{ inputs.BOOST_ARCHIVE_NAME }}
         cd ${{ inputs.BOOST_FOLDER_NAME }}
         .\bootstrap.bat
+        # Build the libs for:
+        # - Atomic - https://www.boost.org/libs/atomic/
+        # - Thread - https://www.boost.org/libs/thread/
+        # - Chrono - https://www.boost.org/libs/chrono/
         .\b2 address-model=${{ inputs.ARCH_ADDRESS_MODEL }} --with-atomic --with-thread --with-chrono install
         cd ..
         Remove-Item ${{ inputs.BOOST_FOLDER_NAME }} -Recurse -Force

scripts/install-boost.sh

@@ -15,5 +15,8 @@ TARBALL_NAME=boost_$(echo "$1" | tr . _)
 curl --fail --silent --show-error --location "https://archives.boost.io/release/${1}/source/${TARBALL_NAME}.tar.gz" | tar xzf -
 pushd "${TARBALL_NAME}"
 ./bootstrap.sh
+# Build the libs for:
+# - Thread - https://www.boost.org/libs/thread/
+# - Atomic - https://www.boost.org/libs/atomic/
 ./b2 --with-thread --with-chrono install
 popd