doc: Add fpi-data section to the docs

doc/libfprint-docs.xml

@@ -44,6 +44,7 @@
     <xi:include href="xml/fpi-poll.xml"/>
     <xi:include href="xml/fpi-img.xml"/>
     <xi:include href="xml/fpi-assembling.xml"/>
+    <xi:include href="xml/fpi-data.xml"/>
     <xi:include href="xml/fpi-usb.xml"/>
   </part>
 

doc/libfprint-sections.txt

@@ -230,6 +230,16 @@ fpi_assemble_frames
 fpi_assemble_lines
 </SECTION>
 
+<SECTION>
+<INCLUDE>fpi-data.h</INCLUDE>
+<FILE>fpi-data</FILE>
+fp_print_data_type
+fp_print_data_item
+
+fpi_print_data_new
+fpi_print_data_item_new
+</SECTION>
+
 <SECTION>
 <INCLUDE>fpi-usb.h</INCLUDE>
 <FILE>fpi-usb</FILE>

libfprint/fpi-data.c

@@ -63,6 +63,15 @@ struct fpi_print_data_item_fp2 {
  * in any fashion that suits you.
  */
 
+/**
+ * SECTION: fpi-data
+ * @title: Stored prints creation
+ *
+ * Stored print can be loaded and created by certain drivers which do their own
+ * print matching in hardware. Most drivers will not be using those functions.
+ * See #fp_print_data for the public API counterpart.
+ */
+
 static char *base_store = NULL;
 
 static void storage_setup(void)