docs: devicetree: fix typo in writing-schema.rst

Fixes a spelling mistake in writing-schema.rst:
"interpretted" → "interpreted"

Signed-off-by: Santosh Mahto <eisantosh95@gmail.com>
Link: https://lore.kernel.org/r/20250820181013.17817-1-eisantosh95@gmail.com


Signed-off-by: Rob Herring (Arm) <robh@kernel.org>