ref-manual: add clarification for SRCREV

It was not clear to me what a "full revision identifier" was in the
context of the note documenting SRCREV.  After clarification via IRC,
this submission attempts to clarify what is meant to help future
readers.

(From yocto-docs rev: c570732cededffa2992173e6c43de4845a1d7d44)

Signed-off-by: Ed Beroset <beroset@ieee.org>
Reviewed-by: Michael Opdenacker <michael.opdenacker@bootlin.com>
Signed-off-by: Steve Sakoman <steve@sakoman.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/documentation/ref-manual/variables.rst b/documentation/ref-manual/variables.rst
index 968e8d6e05..9aab6e0709 100644
--- a/documentation/ref-manual/variables.rst
+++ b/documentation/ref-manual/variables.rst
@@ -7298,7 +7298,7 @@ system and gives an overview of their function and contents.
       that if you want to build a fixed revision and you want to avoid
       performing a query on the remote repository every time BitBake parses
       your recipe, you should specify a :term:`SRCREV` that is a full revision
-      identifier and not just a tag.
+      identifier (e.g. the full SHA hash in git) and not just a tag.
 
       .. note::