TBR: playground: Remove .v23 from all .gitignore files.

MultiPart: 20/25

Change-Id: I83dac52d1881ac8a93a6ca0b8ebb547e4faeacef
diff --git a/.gitignore b/.gitignore
index 81fa255..a83fdb3 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,7 +1,3 @@
 /.jiri
-#TODO(nlacasse): Get rid of .v23 below once v23->jiri transition is complete.
 go/bin
 go/pkg
-
-# Vanadium
-/.v23