When a doctest fails, run further doctests

Instead of stopping running doctests even in other packages.

This change only applies to the `test-fast` job on CI. It does not
affect any default configuration for doctests, nor the `justfile`.

The reason for making this change before fixing the remaining
doctest failure (which is in `gix-pack/src/index/mod.rs`) is to
confirm that it takes effect on CI.

Author: EliahKagan

.github/workflows/ci.yml

@@ -76,7 +76,7 @@ jobs:
           GIX_TEST_CREATE_ARCHIVES_EVEN_ON_CI: 1
         run: cargo nextest run --workspace --no-fail-fast
       - name: Doctest
-        run: cargo test --workspace --doc
+        run: cargo test --workspace --doc --no-fail-fast
       - name: Check that tracked archives are up to date
         run: git diff --exit-code  # If this fails, the fix is usually to commit a regenerated archive.