mv coccinelle/ tools/

I also decided to lowercase semantic patch file names, and to not
mislead people about the WS_Reserve change being a vmod-only thing.

doc/changes.rst

@@ -63,8 +63,8 @@ C APIs (for vmod and utility authors)
     It will only leave the workspace reserved if the reservation
     request could be fulfilled.
 
-  We provide a script to automate this change in the ``coccinelle``
-  subdirectory of the source tree.
+  We provide a script to help automate this change in the
+  ``tools/coccinelle`` subdirectory of the source tree.
 
 ================================
 Varnish Cache 6.2.0 (2019-03-15)

coccinelle/README.rst → tools/coccinelle/README.rst

-This directory contains `coccinelle`_ patches to facilitate code
+This directory contains `coccinelle`_ semantic patches to facilitate code
 maintenance.
 
-Each patch should, in a comment section, explain its purpose.
+Each patch should, in a comment section, explain its purpose. They may be fit
+for both the in-tree code style or out-of-tree VMOD and VUT development.
 
 Unless noted otherwise, all patches should work when invoked as::
 

coccinelle/vmod/WS_Reserve.cocci → tools/coccinelle/ws_reserve.cocci

 /*
- * patch to change code with respect to #2969: Replacement of
+ * Patch to change code with respect to #2969: Replacement of
  * WS_Reserve(ws, sz) by WS_ReserveAll(ws) / WS_ReserveSize(ws, sz)
  *
  * NOTE this patch does not check/fix error handling: