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: ed6f24518c47ecc42a6ef99c35af0f8e0df40e5e)

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 32359291b2..fc29e476cd 100644
--- a/documentation/ref-manual/variables.rst
+++ b/documentation/ref-manual/variables.rst
@@ -7787,7 +7787,7 @@ 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::