[librsvg: 2/4] Add the performance tracking project to the Contributing one.

[Marge Bot <marge-bot src gnome org>]

commit 7d570f5ac53c25795ed6ee7d8afeb28fe1a30cf8
Author: Federico Mena Quintero <federico gnome org>
Date:   Thu Sep 22 13:46:48 2022 -0500

    Add the performance tracking project to the Contributing one.
    
    Part-of: <https://gitlab.gnome.org/GNOME/librsvg/-/merge_requests/751>

 devel-docs/contributing.rst | 7 +++++++
 1 file changed, 7 insertions(+)
---
diff --git a/devel-docs/contributing.rst b/devel-docs/contributing.rst
index d6c56231e..576f63c2d 100644
--- a/devel-docs/contributing.rst
+++ b/devel-docs/contributing.rst
@@ -98,3 +98,10 @@ implementation advice.  It requires some substantial preliminary work,
 like completing the separation between specified values and computed
 values in librsvg's CSS implementation.  Please ask the maintainer to
 prioritize this work if you intend to implement CSS calc().
+
+Performance tracking
+--------------------
+
+See the - :doc:`performance_tracking` document.  This does not involve
+hacking on librsvg itself, but rather creating an infrastructure to
+track performance metrics.