correct typo "allows to place"

Signed-off-by: Daniel Bergey <bergey@alum.mit.edu>
Signed-off-by: Catalin Marinas <catalin.marinas@gmail.com>
diff --git a/stgit/commands/sink.py b/stgit/commands/sink.py
index 4b7535e..34e938f 100644
--- a/stgit/commands/sink.py
+++ b/stgit/commands/sink.py
@@ -33,7 +33,7 @@
 
 If no patch is specified on command-line, the current patch gets sunk.
 By default patches are sunk to the bottom of the stack, but the '--to'
-option allows to place them under any applied patch.
+option allows one to place them under any applied patch.
 
 Sinking internally involves popping all patches (or all patches
 including <target patch>), then pushing the patches to sink, and then