Local docs generation fails on multiline Literate #src blocks

On clean origin/main at 0bb35b4, the non-CI docs build fails while regenerating the Gray-Scott tutorial.

Reproduction (Julia 1.12.6):

timeout 3600 env -u CI julia +release --project=docs -e 'using Pkg; Pkg.instantiate(); include("docs/make.jl")'\n```\n\nThe first error is a malformed generated `Axis(...)` block from `docs/src/literate_tutorials/gray_scott_model_turing_patterns_from_a_coupled_reaction_diffusion_system.jl:96-98` (and the analogous block at lines 105-107). The surrounding source-only lines end in `#src`, but those continuation lines do not. Literate 2.21 therefore leaves an incomplete fragment in the generated page.\n\nIn an isolated clean-main worker, adding `#src` to those six continuation lines lets Gray-Scott generation complete. The next tutorial then fails for the same reason at `docs/src/literate_tutorials/mean_exit_time.jl:350-352`; the multiline `@test_reference joinpath(...)` has `#src` only on its closing line. A scan shows the same legacy pattern in several other literate tutorials, so this needs a focused generator-source audit rather than one-off changes in the strict SciMLTesting/public-API PR.\n\nThe `CI=true` Documenter path does not regenerate Literate sources and is tracked separately from this local-generation failure. No tests or docs errors were silenced.

Start by running the documented Julia command and inspect docs/src/literate_tutorials/gray_scott_model_turing_patterns_from_a_coupled_reaction_diffusion_system.jl lines 96-98 and 105-107, then docs/src/literate_tutorials/mean_exit_time.jl lines 350-352. Audit the other literate tutorial sources for multiline source-only blocks whose continuation lines lack #src. Done means local non-CI docs generation completes without malformed generated blocks or errors.