Moved test_cases page to be index

Signed-off-by: Martyn Welch <martyn.welch@collabora.com>

content/18.06/releasenotes.md

@@ -115,7 +115,7 @@ of failing tests.
 ### Testcase prioritization
 
 A priority level has been assigned to each
-[testcase]( {{< ref "/qa/test_cases.md" >}} ) in order to better schedule their
+[testcase]( {{< ref "/qa/test_cases/_index.md" >}} ) in order to better schedule their
 execution, to clearly identify release blockers and to prioritize
 maintainance and improvements.
 
@@ -722,4 +722,4 @@ services.
   - webkit2gtk-drag-and-drop doesn't work with touch
 
   - Icons for Apps like Music Settings are missing on the OSTree based
-    images
\ No newline at end of file
+    images

content/18.12/releasenotes.md

@@ -216,7 +216,7 @@ process](https://designs.apertis.org/latest/contribution-process.html).
 
 #### Test case definitions on the wiki
 
-The definitions under [QA/Test_Cases]( {{< ref "/qa/test_cases.md" >}} ) are
+The definitions under [QA/Test_Cases]( {{< ref "/qa/test_cases/_index.md" >}} ) are
 now deprecated in favour of the YAML-based definitions in the
 [apertis-test-cases](https://gitlab.apertis.org/tests/apertis-test-cases/)
 repository, see the [\#Improvements to the test
@@ -846,4 +846,4 @@ services.
   - folks-telepathy: folks-retrieve-contacts-telepathy test failed
 
   - apparmor-folks: R1.13b_folks-retrieve-contacts-telepathy test
-    failed
\ No newline at end of file
+    failed