[gtkmm-documentation] Make conversions between std::string and Glib::ustring explicit

[Kjell Ahlstedt <kjellahl src gnome org>]

commit df80ad0b44bd2a3636c80e18f126f7566a9e52cd
Author: Kjell Ahlstedt <kjellahlstedt gmail com>
Date:   Mon Nov 18 10:23:32 2019 +0100

    Make conversions between std::string and Glib::ustring explicit

 examples/book/buildapp/step3/exampleappwindow.cc | 2 +-
 examples/book/buildapp/step5/exampleappwindow.cc | 2 +-
 examples/book/buildapp/step6/exampleappwindow.cc | 2 +-
 examples/book/buildapp/step7/exampleappwindow.cc | 2 +-
 examples/book/buildapp/step8/exampleappwindow.cc | 2 +-
 examples/book/buildapp/step9/exampleappwindow.cc | 2 +-
 examples/book/giomm/write_file/main.cc           | 2 +-
 examples/others/calendar/calendar.cc             | 2 +-
 8 files changed, 8 insertions(+), 8 deletions(-)
---
diff --git a/examples/book/buildapp/step3/exampleappwindow.cc 
b/examples/book/buildapp/step3/exampleappwindow.cc
index 806369c..1ff4e38 100644
--- a/examples/book/buildapp/step3/exampleappwindow.cc
+++ b/examples/book/buildapp/step3/exampleappwindow.cc
@@ -43,7 +43,7 @@ ExampleAppWindow* ExampleAppWindow::create()
 
 void ExampleAppWindow::open_file_view(const Glib::RefPtr<Gio::File>& file)
 {
-  const auto basename = file->get_basename();
+  const Glib::ustring basename = file->get_basename();
 
   auto scrolled = Gtk::make_managed<Gtk::ScrolledWindow>();
   scrolled->set_hexpand(true);
diff --git a/examples/book/buildapp/step5/exampleappwindow.cc 
b/examples/book/buildapp/step5/exampleappwindow.cc
index 2e7d5ea..5988939 100644
--- a/examples/book/buildapp/step5/exampleappwindow.cc
+++ b/examples/book/buildapp/step5/exampleappwindow.cc
@@ -47,7 +47,7 @@ ExampleAppWindow* ExampleAppWindow::create()
 
 void ExampleAppWindow::open_file_view(const Glib::RefPtr<Gio::File>& file)
 {
-  const auto basename = file->get_basename();
+  const Glib::ustring basename = file->get_basename();
 
   auto scrolled = Gtk::make_managed<Gtk::ScrolledWindow>();
   scrolled->set_hexpand(true);
diff --git a/examples/book/buildapp/step6/exampleappwindow.cc 
b/examples/book/buildapp/step6/exampleappwindow.cc
index 6a26f7d..387aa58 100644
--- a/examples/book/buildapp/step6/exampleappwindow.cc
+++ b/examples/book/buildapp/step6/exampleappwindow.cc
@@ -72,7 +72,7 @@ ExampleAppWindow* ExampleAppWindow::create()
 
 void ExampleAppWindow::open_file_view(const Glib::RefPtr<Gio::File>& file)
 {
-  const auto basename = file->get_basename();
+  const Glib::ustring basename = file->get_basename();
 
   auto scrolled = Gtk::make_managed<Gtk::ScrolledWindow>();
   scrolled->set_hexpand(true);
diff --git a/examples/book/buildapp/step7/exampleappwindow.cc 
b/examples/book/buildapp/step7/exampleappwindow.cc
index 20cf42b..e8e127a 100644
--- a/examples/book/buildapp/step7/exampleappwindow.cc
+++ b/examples/book/buildapp/step7/exampleappwindow.cc
@@ -105,7 +105,7 @@ ExampleAppWindow* ExampleAppWindow::create()
 
 void ExampleAppWindow::open_file_view(const Glib::RefPtr<Gio::File>& file)
 {
-  const auto basename = file->get_basename();
+  const Glib::ustring basename = file->get_basename();
 
   auto scrolled = Gtk::make_managed<Gtk::ScrolledWindow>();
   scrolled->set_hexpand(true);
diff --git a/examples/book/buildapp/step8/exampleappwindow.cc 
b/examples/book/buildapp/step8/exampleappwindow.cc
index 4282e7b..8997687 100644
--- a/examples/book/buildapp/step8/exampleappwindow.cc
+++ b/examples/book/buildapp/step8/exampleappwindow.cc
@@ -122,7 +122,7 @@ ExampleAppWindow* ExampleAppWindow::create()
 
 void ExampleAppWindow::open_file_view(const Glib::RefPtr<Gio::File>& file)
 {
-  const auto basename = file->get_basename();
+  const Glib::ustring basename = file->get_basename();
 
   auto scrolled = Gtk::make_managed<Gtk::ScrolledWindow>();
   scrolled->set_hexpand(true);
diff --git a/examples/book/buildapp/step9/exampleappwindow.cc 
b/examples/book/buildapp/step9/exampleappwindow.cc
index 3cc57ef..1d4d62d 100644
--- a/examples/book/buildapp/step9/exampleappwindow.cc
+++ b/examples/book/buildapp/step9/exampleappwindow.cc
@@ -132,7 +132,7 @@ ExampleAppWindow* ExampleAppWindow::create()
 
 void ExampleAppWindow::open_file_view(const Glib::RefPtr<Gio::File>& file)
 {
-  const auto basename = file->get_basename();
+  const Glib::ustring basename = file->get_basename();
 
   auto scrolled = Gtk::make_managed<Gtk::ScrolledWindow>();
   scrolled->set_hexpand(true);
diff --git a/examples/book/giomm/write_file/main.cc b/examples/book/giomm/write_file/main.cc
index cd50eab..cc725b1 100644
--- a/examples/book/giomm/write_file/main.cc
+++ b/examples/book/giomm/write_file/main.cc
@@ -43,7 +43,7 @@ int main(int /* argc */, char** /* argv */)
       std::cerr << "Gio::File::create_file() returned an empty RefPtr." << std::endl;
 
     Glib::ustring contents = "This is some test output";
-    const gsize bytes_read = stream->write(contents);
+    const gsize bytes_read = stream->write(contents.raw());
 
     if(bytes_read)
       std::cout << "File contents written: " << contents << std::endl;
diff --git a/examples/others/calendar/calendar.cc b/examples/others/calendar/calendar.cc
index 2a73566..b46d9d9 100644
--- a/examples/others/calendar/calendar.cc
+++ b/examples/others/calendar/calendar.cc
@@ -128,7 +128,7 @@ void CalendarExample::on_font_button_font_set()
     (font_size == 0 ? "" : "    font-size: " + std::to_string(font_size / PANGO_SCALE) + "pt;\n") +
     "}";
 
-  css_provider_->load_from_data(css);
+  css_provider_->load_from_data(css.raw());
 }
 
 void CalendarExample::on_button_close()