Windows: Use the Windows style PATH separator ';'.

Signed-off-by: Johannes Sixt <johannes.sixt@telecom.at>
diff --git a/Documentation/git.txt b/Documentation/git.txt
index 7414238..4e4bd6d 100644
--- a/Documentation/git.txt
+++ b/Documentation/git.txt
@@ -409,9 +409,9 @@
 'GIT_ALTERNATE_OBJECT_DIRECTORIES'::
 	Due to the immutable nature of git objects, old objects can be
 	archived into shared, read-only directories. This variable
-	specifies a ":" separated list of git object directories which
-	can be used to search for git objects. New objects will not be
-	written to these directories.
+	specifies a ":" separated (on Windows ";" separated) list
+	of git object directories which can be used to search for git
+	objects. New objects will not be written to these directories.
 
 'GIT_DIR'::
 	If the 'GIT_DIR' environment variable is set then it