patch 9.0.2025: no cmdline completion for ++opt args

Problem:  no cmdline completion for ++opt args
Solution: Add cmdline completion for :e ++opt=arg and :terminal
          [++options]

closes: #13319

Signed-off-by: Christian Brabandt <cb@256bit.org>
Co-authored-by: Yee Cheng Chin <ychin.git@gmail.com>
diff --git a/runtime/doc/cmdline.txt b/runtime/doc/cmdline.txt
index 6d58d63..c5d0096 100644
--- a/runtime/doc/cmdline.txt
+++ b/runtime/doc/cmdline.txt
@@ -387,6 +387,7 @@
 word before the cursor.  This is available for:
 
 - Command names: At the start of the command-line.
+- |++opt| values.
 - Tags: Only after the ":tag" command.
 - File names: Only after a command that accepts a file name or a setting for
   an option that can be set to a file name.  This is called file name