Documentation: Kunit: Fix inconsistent titles

Use the same wording when citing and describing Kunit parts.
Signed-off-by: Tales Aparecida <tales.aparecida@gmail.com>
Reviewed-by: David Gow <davidgow@google.com>
Reviewed-by: Sadiya Kazi <sadiyakazi@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

Documentation/dev-tools/kunit/architecture.rst

@@ -6,8 +6,8 @@ KUnit Architecture
 
 The KUnit architecture can be divided into two parts:
 
-- Kernel testing library
-- kunit_tool (Command line test harness)
+- `In-Kernel Testing Framework`_
+- `kunit_tool (Command Line Test Harness)`_
 
 In-Kernel Testing Framework
 ===========================