girparser: Handle doc:format element in root:repository

See https://gitlab.gnome.org/GNOME/gobject-introspection/-/issues/448

Fixes https://gitlab.gnome.org/GNOME/vala/issues/1586

tests/Makefile.am

@@ -905,6 +905,7 @@ TESTS = \
 	gir/delegate-closure-destroy-index-conflict.gir \
 	gir/delegate-error-pos.gir \
 	gir/dev_t.gir \
+	gir/doc-format.gir \
 	gir/enum.gir \
 	gir/errordomain.gir \
 	gir/gid_t.gir \

tests/gir/doc-format.gir

@@ -0,0 +1,11 @@
+<?xml version="1.0"?>
+<repository version="1.2" xmlns="http://www.gtk.org/introspection/core/1.0" xmlns:c="http://www.gtk.org/introspection/c/1.0" xmlns:glib="http://www.gtk.org/introspection/glib/1.0">
+<include name="GObject" version="2.0"/>
+<include name="GLib" version="2.0"/>
+<include name="Gio" version="2.0"/>
+<package name="test"/>
+<c:include name="test.h"/>
+<doc:format name="unknown"/>
+<namespace name="Test" version="1.0" shared-library="test" c:prefix="Test" c:identifier-prefixes="Test" c:symbol-prefixes="test">
+</namespace>
+</repository>

tests/gir/doc-format.vapi-expected

@@ -0,0 +1,3 @@
+[CCode (cprefix = "Test", gir_namespace = "Test", gir_version = "1.0", lower_case_cprefix = "test_")]
+namespace Test {
+}

vala/valagirparser.vala

@@ -2103,6 +2103,9 @@ public class Vala.GirParser : CodeVisitor {
 				}
 			} else if (reader.name == "c:include") {
 				parse_c_include ();
+			} else if (reader.name == "doc:format") {
+				//TODO Handle this format information properly
+				skip_element ();
 			} else {
 				// error
 				Report.error (get_current_src (), "unknown child element `%s' in `repository'", reader.name);