[fractal] ui: Unmark placeholders as translatable

[Daniel Garcia Moreno <danigm src gnome org>]

commit a10c7c4ad6136bd93dc144d1e601f6939c56f819
Author: Christopher Davis <brainblasted disroot org>
Date:   Mon Apr 29 10:50:44 2019 -0400

    ui: Unmark placeholders as translatable
    
    As per https://gitlab.gnome.org/GNOME/fractal/issues/397,
    removes translation for strings that are replaces and
    translated within the code.
    
    Fixes #397

 fractal-gtk/res/ui/account_settings.ui | 9 ++++++---
 fractal-gtk/res/ui/invite.ui           | 3 ++-
 fractal-gtk/res/ui/main_window.ui      | 6 ++++--
 fractal-gtk/res/ui/media_viewer.ui     | 3 ++-
 4 files changed, 14 insertions(+), 7 deletions(-)
---
diff --git a/fractal-gtk/res/ui/account_settings.ui b/fractal-gtk/res/ui/account_settings.ui
index f7670911..8e7730b1 100644
--- a/fractal-gtk/res/ui/account_settings.ui
+++ b/fractal-gtk/res/ui/account_settings.ui
@@ -320,7 +320,8 @@
                                     <property name="visible">True</property>
                                     <property name="can_focus">False</property>
                                     <property name="halign">start</property>
-                                    <property name="label" translatable="yes">None</property>
+                                    <!-- Translators: This string is replaced not user-visible -->
+                                    <property name="label">None</property>
                                   </object>
                                   <packing>
                                     <property name="left_attach">1</property>
@@ -348,7 +349,8 @@
                                     <property name="visible">True</property>
                                     <property name="can_focus">False</property>
                                     <property name="halign">start</property>
-                                    <property name="label" translatable="yes">None</property>
+                                    <!-- Translators: This string is replaced not user-visible -->
+                                    <property name="label">None</property>
                                   </object>
                                   <packing>
                                     <property name="left_attach">1</property>
@@ -376,7 +378,8 @@
                                     <property name="visible">True</property>
                                     <property name="can_focus">False</property>
                                     <property name="halign">start</property>
-                                    <property name="label" translatable="yes">None</property>
+                                    <!-- Translators: This string is replaced not user-visible -->
+                                    <property name="label">None</property>
                                   </object>
                                   <packing>
                                     <property name="left_attach">1</property>
diff --git a/fractal-gtk/res/ui/invite.ui b/fractal-gtk/res/ui/invite.ui
index 19ec92fc..c31b0823 100644
--- a/fractal-gtk/res/ui/invite.ui
+++ b/fractal-gtk/res/ui/invite.ui
@@ -16,7 +16,8 @@
     <property name="transient_for">main_window</property>
     <property name="message_type">question</property>
     <property name="text" translatable="yes">Invitation</property>
-    <property name="secondary_text" translatable="yes">You’ve been invited to join "", you can accept or 
reject</property>
+    <!-- Translators: This string is replaced not user-visible -->
+    <property name="secondary_text">You’ve been invited to join "", you can accept or reject</property>
     <child internal-child="vbox">
       <object class="GtkBox">
         <property name="can_focus">False</property>
diff --git a/fractal-gtk/res/ui/main_window.ui b/fractal-gtk/res/ui/main_window.ui
index 680e3f52..e4932e73 100644
--- a/fractal-gtk/res/ui/main_window.ui
+++ b/fractal-gtk/res/ui/main_window.ui
@@ -538,7 +538,8 @@
                             <child>
                               <object class="GtkLabel" id="room_name">
                                 <property name="can_focus">False</property>
-                                <property name="label" translatable="yes">Room name</property>
+                                <!-- Translators: This string is replaced not user-visible -->
+                                <property name="label">Room name</property>
                                 <property name="ellipsize">end</property>
                                 <style>
                                   <class name="title"/>
@@ -553,7 +554,8 @@
                             <child>
                               <object class="GtkLabel" id="room_topic">
                                 <property name="can_focus">False</property>
-                                <property name="label" translatable="yes">Room topic</property>
+                                <!-- Translators: This string is replaced not user-visible -->
+                                <property name="label">Room topic</property>
                                 <property name="ellipsize">end</property>
                                 <style>
                                   <class name="subtitle"/>
diff --git a/fractal-gtk/res/ui/media_viewer.ui b/fractal-gtk/res/ui/media_viewer.ui
index c8e5be2f..b59ef33a 100644
--- a/fractal-gtk/res/ui/media_viewer.ui
+++ b/fractal-gtk/res/ui/media_viewer.ui
@@ -227,7 +227,8 @@
       <object class="GtkHeaderBar" id="media_viewer_headerbar">
         <property name="visible">True</property>
         <property name="can_focus">False</property>
-        <property name="title" translatable="yes">Media viewer</property>
+        <!-- Translators: This string is replaced not user-visible -->
+        <property name="title">Media viewer</property>
         <property name="show_close_button">True</property>
         <child>
           <object class="GtkButton" id="media_viewer_back_button">