save vmod developer life time

by providing a trivial tool to rename vmod RST references.

To @Dridi and all other ladybug-lovers: I tried, but gave up after 5'.
Maybe spatch on its own would have done the job, but sed is just so much
simpler and, IMHO, totally appropriate for the job.

doc/changes.rst

@@ -86,6 +86,8 @@ APIs / VMODs
     :ref:`name.obj()`
     :ref:`xobj.method()`
 
+  ``tools/vmod_ref_rename.sh`` is provided to automate this task
+
 ================================
 Varnish Cache 6.2.0 (2019-03-15)
 ================================

tools/vmod_ref_rename.sh

+#!/bin/bash
+
+# trivial sed-based tool to rename RST references in vmod .vcc files
+# to the new scheme as of commit
+# 904ceabf07c294983efcebfe1d614c2d2fd5cdda
+#
+# only tested with GNU sed
+#
+# to be called from a vmod git repository
+#
+# Author: Nils Goroll <nils.goroll@uplex.de>
+#
+# This file is in the public domain
+
+typeset -ra files=($(git ls-files | grep -E '\.vcc$'))
+
+if [[ ${#files[@]} -eq 0 ]] ; then
+    echo >&2 'No vcc files found'
+    exit 0
+fi
+
+if [[ -n $(git status -s) ]] ; then
+    echo >&2 'clean up your tree first'
+    git status
+    exit 1
+fi
+
+set -eu
+
+sed -e 's#`vmod_\([^.]*\)\.\([^.`]*\)`_#`\1.\2()`_#g' \
+    -e 's#`vmod_\([^.]*\)\.\([^.`]*\).\([^.`]*\)`_#`x\2.\3()`_#g' \
+    -i "${files[@]}"
+
+if [[ -z $(git status -s) ]] ; then
+    echo >&2 'no change'
+    exit 0
+fi
+
+git commit -m 'rename vmod RST references (vmod_ref_rename.sh)' \
+    "${files[@]}"
+
+echo DONE - review and test the previous commit