Current logic doesn't use the right value for CONFIG_RUST. Instead,
it picks the value cached from a previous non-doc buid.

After analyzing the issue, it was not caused by changing the logic
to use the wrapper, but, instead, to the way .config is currently
parsed. For more details, see:

    https://lore.kernel.org/linux-doc/20251121101236.5b1f9989@foz.lan/

---

v2: changed patch description to better explain the issue.

Mauro Carvalho Chehab (1):
  docs: makefile: move rustdoc check to the build wrapper

 Documentation/Makefile          |  6 -----
 tools/docs/sphinx-build-wrapper | 41 +++++++++++++++++++++++++--------
 2 files changed, 32 insertions(+), 15 deletions(-)

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2.51.1