Move all references of old url to the new address (#622)

diff --git a/docs/HarfBuzz.png b/docs/HarfBuzz.png
index d58d9fc..170e86e 100644
--- a/docs/HarfBuzz.png
+++ b/docs/HarfBuzz.png
Binary files differ
diff --git a/docs/harfbuzz-docs.xml b/docs/harfbuzz-docs.xml
index 12df833..5182bc5 100644
--- a/docs/harfbuzz-docs.xml
+++ b/docs/harfbuzz-docs.xml
@@ -22,7 +22,7 @@
         source tree is available
         <ulink url="http://cgit.freedesktop.org/harfbuzz/">here</ulink>.
         Also available on
-        <ulink url="https://github.com/behdad/harfbuzz">github</ulink>.
+        <ulink url="https://github.com/harfbuzz/harfbuzz">github</ulink>.
         See <xref linkend="download" endterm="download.title"/> for release tarballs.
       </para>
       <para>
diff --git a/docs/usermanual-install-harfbuzz.xml b/docs/usermanual-install-harfbuzz.xml
index be8ac8d..24f54e3 100644
--- a/docs/usermanual-install-harfbuzz.xml
+++ b/docs/usermanual-install-harfbuzz.xml
@@ -12,7 +12,7 @@
     <para>
       The canonical source tree is available
       <ulink url="http://cgit.freedesktop.org/harfbuzz/">here</ulink>.
-      Also available on <ulink url="https://github.com/behdad/harfbuzz">github</ulink>.
+      Also available on <ulink url="https://github.com/harfbuzz/harfbuzz">github</ulink>.
     </para>
     <para>
       The API that comes with <filename class='headerfile'>hb.h</filename> will