docs/vm: rename documentation files to .rst

Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 87ab9b8..6d59116 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1185,7 +1185,7 @@
 	 * mmu_notifier_invalidate_range_end() happens which can lead to a
 	 * device seeing memory write in different order than CPU.
 	 *
-	 * See Documentation/vm/mmu_notifier.txt
+	 * See Documentation/vm/mmu_notifier.rst
 	 */
 	pmdp_huge_clear_flush_notify(vma, haddr, vmf->pmd);
 
@@ -2037,7 +2037,7 @@
 	 * replacing a zero pmd write protected page with a zero pte write
 	 * protected page.
 	 *
-	 * See Documentation/vm/mmu_notifier.txt
+	 * See Documentation/vm/mmu_notifier.rst
 	 */
 	pmdp_huge_clear_flush(vma, haddr, pmd);