char: misc: improve testing Kconfig description

Describe that it tests the miscdevice API and include the usual disclaimer
about KUnit not being fit for production kernels.

While at it, also fix KUnit capitalization.

Signed-off-by: Thadeu Lima de Souza Cascardo <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

lib/Kconfig.debug

···
 	tristate "Perform selftest on IDA functions"
 
 config TEST_MISC_MINOR
-	tristate "Basic misc minor Kunit test" if !KUNIT_ALL_TESTS
+	tristate "miscdevice KUnit test" if !KUNIT_ALL_TESTS
 	depends on KUNIT
 	default KUNIT_ALL_TESTS
 	help
-	  Kunit test for the misc minor.
-	  It tests misc minor functions for dynamic and misc dynamic minor.
-	  This include misc_xxx functions
+	  Kunit test for miscdevice API, specially its behavior in respect to
+	  static and dynamic minor numbers.
+
+	  KUnit tests run during boot and output the results to the debug log
+	  in TAP format (https://testanything.org/). Only useful for kernel devs
+	  running the KUnit test harness, and not intended for inclusion into a
+	  production build.
+
+	  For more information on KUnit and unit tests in general please refer
+	  to the KUnit documentation in Documentation/dev-tools/kunit/.
 
 	  If unsure, say N.