doc: Update docs images README with required ditaa version

The URL for Ditaa linked to the old Sourceforge version which is
too old for what we need, the fork over on Github is the correct
version to use for re-generating the SVG files for the docs. The
required Ditaa version is 0.11.0 as it when SVG support as added.
Running the version found on Sourceforge produce the error below:

$ ditaa -E -S --svg in.txt out.txt
Unrecognized option: --svg
usage: ditaa <INPFILE> [OUTFILE] [-A] [-b <BACKGROUND>] [-d] [-E] [-e
      <ENCODING>] [-h] [--help] [-o] [-r] [-S] [-s <SCALE>] [-T] [-t
      <TABS>] [-v] [-W]

While there, also mention that meson rules exists for building
images.

Author: Nazir Bilal Yavuz <byavuz81@gmail.com>
Reviewed-by: Daniel Gustafsson <daniel@yesql.se>
Reviewed-by: Paul A Jungwirth <pj@illuminatedcomputing.com>
Discussion: https://postgr.es/m/CAN55FZ2O-23xERF2NYcvv9DM_1c9T16y6mi3vyP=O1iuXS0ASA@mail.gmail.com

diff --git a/doc/src/sgml/images/README b/doc/src/sgml/images/README
index 07c458025534575100dc950b6b99a6647b4fa4bc..93b75485c446420e18a5bbf1b6a9699d9cdfee32 100644 (file)
--- a/doc/src/sgml/images/README
+++ b/doc/src/sgml/images/README
@@ -13,14 +13,14 @@ involve diffable source files.
 These tools are acceptable:
 
 - Graphviz (https://graphviz.org/)
-- Ditaa (http://ditaa.sourceforge.net/)
+- Ditaa v0.11.0 or later (https://github.com/stathissideris/ditaa)
 
 We use SVG as the format for integrating the image into the ultimate
 output formats of the documentation, that is, HTML, PDF, and others.
 Therefore, any tool used needs to be able to produce SVG.
 
-This directory contains makefile rules to build SVG from common input
-formats, using some common styling.
+This directory contains makefile and meson rules to build SVG from common
+input formats, using some common styling.
 
 fixup-svg.xsl applies some postprocessing to the SVG files produced by
 those external tools to address assorted issues.  See comments in