doc: Include the documentation for CoglEuler

Several little changes were needed to make the CoglEuler documentation
appear:

  • Fix the embeded docbook snippet in the CoglEuler section header
  • Add the xinclude directive to the main document
  • Add the missing <SECTION> in -sections.txt

Reviewed-by: Robert Bragg <robert@linux.intel.com>

(cherry picked from commit c7f6e07f7b8ba0d7dc9604e888c8a46165ec3ed4)

cogl/cogl-euler.h

@@ -62,7 +62,7 @@ G_BEGIN_DECLS
  * <listitem>
  * Easy to understand and use, compared to quaternions and matrices,
  * so may be a good choice for a user interface.
- * <listitem>
+ * </listitem>
  * <listitem>
  * Efficient storage, needing only 3 components any rotation can be
  * represented.
@@ -105,7 +105,7 @@ G_BEGIN_DECLS
  * slightly different aeronautical terms, such as "yaw" instead of
  * "heading" or "bank" instead of "roll".
  * </listitem>
- * </itemlist>
+ * </itemizedlist>
  *
  * To minimize the aliasing issue we may refer to "Canonical Euler"
  * angles where heading and roll are restricted to +- 180° and pitch is

doc/reference/cogl-2.0-experimental/cogl-2.0-experimental-docs.xml.in

@@ -125,6 +125,7 @@
       <xi:include href="xml/cogl-color.xml"/>
       <xi:include href="xml/cogl-matrix.xml"/>
       <xi:include href="xml/cogl-vector.xml"/>
+      <xi:include href="xml/cogl-euler.xml"/>
       <xi:include href="xml/cogl-quaternion.xml"/>
       <xi:include href="xml/cogl-types.xml"/>
       <xi:include href="xml/cogl-version.xml"/>

doc/reference/cogl-2.0-experimental/cogl-2.0-experimental-sections.txt

@@ -566,6 +566,7 @@ cogl_matrix_project_points
 cogl_matrix_is_identity
 </SECTION>
 
+<SECTION>
 <FILE>cogl-euler</FILE>
 <TITLE>Eulers (Rotations)</TITLE>
 CoglEuler