doc: fix typo in user manual

The sentence following the git tag command continues the
preceding sentence, so "You" should be lowercase.

Signed-off-by: Khan Zimov <kaliugov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/user-manual.adoc

diff --git a/Documentation/user-manual.adoc b/Documentation/user-manual.adoc
index 5ec65ce..1652ab3 100644
--- a/Documentation/user-manual.adoc
+++ b/Documentation/user-manual.adoc
@@ -632,7 +632,7 @@
 $ git tag stable-1 1b2e1d63ff
 -------------------------------------------------
 
-You can use `stable-1` to refer to the commit 1b2e1d63ff.
+you can use `stable-1` to refer to the commit 1b2e1d63ff.
 
 This creates a "lightweight" tag.  If you would also like to include a
 comment with the tag, and possibly sign it cryptographically, then you