[PATCH 3/3] docs: writing tests: update cleaning instructions

[Ivan Orlov]

After the changes introduced by the previous patches are applied, there
is no need of the manual removal of the `build/` directory every time
new test is added. Running `make clean` should be enough to regenerate
the carray-related files.

Update the documentation correspondingly.

Signed-off-by: Ivan Orlov <ivan.orlov0322 at gmail.com>
---
 docs/writing_tests.md | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/docs/writing_tests.md b/docs/writing_tests.md
index 0fd15d6..cee4c4d 100644
--- a/docs/writing_tests.md
+++ b/docs/writing_tests.md
@@ -57,9 +57,7 @@ carray-sbi_unit_tests-$(CONFIG_SBIUNIT) += string_test_suite
 libsbi-objs-$(CONFIG_SBIUNIT) += tests/sbi_string_test.o
 ```
 
-If you compiled OpenSBI with CONFIG_SBIUNIT enabled before, you may need to
-manually remove the build folder in order to regenerate the carray files:
-`rm -rf build/`.
+Now, run `make clean` in order to regenerate the carray-related files.
 
 Recompile OpenSBI with the CONFIG_SBIUNIT option enabled and run it in QEMU.
 You will see something like this:
-- 
2.34.1