patch 8.0.1361: some users don't want to diff with hidden buffers
Problem: Some users don't want to diff with hidden buffers.
Solution: Add the "hiddenoff" item to 'diffopt'. (Alisue, closes #2394)
diff --git a/runtime/doc/options.txt b/runtime/doc/options.txt
index 5df5f30..08bc78d 100644
--- a/runtime/doc/options.txt
+++ b/runtime/doc/options.txt
@@ -2634,6 +2634,9 @@
vertical Start diff mode with vertical splits (unless
explicitly specified otherwise).
+ hiddenoff Do not use diff mode for a buffer when it
+ becomes hidden.
+
foldcolumn:{n} Set the 'foldcolumn' option to {n} when
starting diff mode. Without this 2 is used.