Documentation: Expand a couple of abbreviations

These may not be obvious to non-native English speakers

Signed-off-by: Mike Ralphson <mike@abacus.co.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/Documentation/gitk.txt b/Documentation/gitk.txt
index bd005bc..cf465cb 100644
--- a/Documentation/gitk.txt
+++ b/Documentation/gitk.txt
@@ -74,7 +74,7 @@
 <path>...::
 
 	Limit commits to the ones touching files in the given paths. Note, to
-	avoid ambiguity wrt. revision names use "--" to separate the paths
+	avoid ambiguity with respect to revision names use "--" to separate the paths
 	from any preceding options.
 
 Examples