Documentation: kunit: Fix cross-referencing warnings

The Architecture chapter of the KUnit documentation tried to include
copies of the kernel-doc for a couple of things, despite these already
existing in the API documentation. This lead to some warnings:

architecture:31: ./include/kunit/test.h:3: WARNING: Duplicate C declaration, also defined at dev-tools/kunit/api/test:66.
Declaration is '.. c:struct:: kunit_case'.
architecture:163: ./include/kunit/test.h:1217: WARNING: Duplicate C declaration, also defined at dev-tools/kunit/api/test:1217.
Declaration is '.. c:macro:: KUNIT_ARRAY_PARAM'.
architecture.rst:3: WARNING: Duplicate C declaration, also defined at dev-tools/kunit/api/test:66.
Declaration is '.. c:struct:: kunit_case'.
architecture.rst:1217: WARNING: Duplicate C declaration, also defined at dev-tools/kunit/api/test:1217.
Declaration is '.. c:macro:: KUNIT_ARRAY_PARAM'.

Get rid of these, and cleanup the mentions of the struct and macro in
question so that sphinx generates a link to the existing copy of the
documentation in the api/test document.

Fixes: bc145b37 ("Documentation: KUnit: Added KUnit Architecture")
Signed-off-by: David Gow <davidgow@google.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Tested-by: Brendan Higgins <brendanhiggins@google.com>
Link: https://lore.kernel.org/r/20220326054414.637293-1-davidgow@google.comSigned-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/dev-tools/kunit/architecture.rst

@@ -26,10 +26,7 @@ The fundamental unit in KUnit is the test case. The KUnit test cases are
 grouped into KUnit suites. A KUnit test case is a function with type
 signature ``void (*)(struct kunit *test)``.
 These test case functions are wrapped in a struct called
-``struct kunit_case``. For code, see:
-
-.. kernel-doc:: include/kunit/test.h
-	:identifiers: kunit_case
+struct kunit_case.
 
 .. note:
 	``generate_params`` is optional for non-parameterized tests.
@@ -152,18 +149,12 @@ Parameterized Tests
 Each KUnit parameterized test is associated with a collection of
 parameters. The test is invoked multiple times, once for each parameter
 value and the parameter is stored in the ``param_value`` field.
-The test case includes a ``KUNIT_CASE_PARAM()`` macro that accepts a
+The test case includes a KUNIT_CASE_PARAM() macro that accepts a
 generator function.
 The generator function is passed the previous parameter and returns the next
 parameter. It also provides a macro to generate common-case generators based on
 arrays.
 
-For code, see:
-
-.. kernel-doc:: include/kunit/test.h
-	:identifiers: KUNIT_ARRAY_PARAM
-
-
 kunit_tool (Command Line Test Harness)
 ======================================