pw_persistent_memory: reset() -> invalidate()

Renames reset() to Invalidate(), as it better expresses that the
resulting object will be considered invalid after calling.

Change-Id: I288ac1118b3af80f84a260ee979b81b684a43b9b
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/41341
Commit-Queue: Armando Montanez <amontanez@google.com>
Pigweed-Auto-Submit: Armando Montanez <amontanez@google.com>
Reviewed-by: Wyatt Hepler <hepler@google.com>
diff --git a/pw_persistent_ram/persistent_test.cc b/pw_persistent_ram/persistent_test.cc
index bd3de4f..8c667ec 100644
--- a/pw_persistent_ram/persistent_test.cc
+++ b/pw_persistent_ram/persistent_test.cc
@@ -62,7 +62,7 @@
     auto& persistent = *(new (&buffer_) Persistent<uint32_t>());
     persistent = 42u;
     EXPECT_TRUE(persistent.has_value());
-    persistent.reset();
+    persistent.Invalidate();
 
     persistent.~Persistent();  // Emulate shutdown / global destructors.
   }