[PATCH rtems-docs] eng/vc-users: Set up patch message with repo name

[Ida Delphine]

From: Meh Mbeh Ida Delphine <idadelm at gmail.com>

Added instructions on how to set up a patch messahe with a repo name.

Author:    Meh Mbeh Ida Delphine <idadelm at gmail.com>
Date:      Tue Mar 16 19:11:23 2021 +0100
---
 eng/vc-users.rst | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/eng/vc-users.rst b/eng/vc-users.rst
index 31de516..772019e 100644
--- a/eng/vc-users.rst
+++ b/eng/vc-users.rst
@@ -458,6 +458,14 @@ specify a version number for your patch, for example, use
 
 to indicate the second version of a patch, ``-v3`` for a third, and so forth.
 
+Also, in order to create a patch specifying the repo name in the patch message, 
+you should use the``--subject-prefix`` flag. For example, if contributing to 
+the rtems-docs repo, use
+
+.. code-block:: shell
+
+  git format-patch HEAD^ --subject-prefix="PATCH rtems-docs"
+
 Patches created using ``git format-patch`` are formatted so they can be emailed
 and rely on having Git configured with your name and email address, for example
 
-- 
2.25.1