[qt] Use tr() instead of _()

Also, `make translate`

src/qt/locale/bitcoin_en.ts

@@ -1121,6 +1121,41 @@
         <source>command-line options</source>
         <translation type="unfinished">command-line options</translation>
     </message>
+    <message>
+        <location line="+9"/>
+        <source>UI Options:</source>
+        <translation type="unfinished"></translation>
+    </message>
+    <message>
+        <location line="+4"/>
+        <source>Choose data directory on startup (default: %u)</source>
+        <translation type="unfinished"></translation>
+    </message>
+    <message>
+        <location line="+1"/>
+        <source>Set language, for example &quot;de_DE&quot; (default: system locale)</source>
+        <translation type="unfinished"></translation>
+    </message>
+    <message>
+        <location line="+1"/>
+        <source>Start minimized</source>
+        <translation type="unfinished"></translation>
+    </message>
+    <message>
+        <location line="+1"/>
+        <source>Set SSL root certificates for payment request (default: -system-)</source>
+        <translation type="unfinished"></translation>
+    </message>
+    <message>
+        <location line="+1"/>
+        <source>Show splash screen on startup (default: %u)</source>
+        <translation type="unfinished"></translation>
+    </message>
+    <message>
+        <location line="+1"/>
+        <source>Reset all settings changes made over the GUI</source>
+        <translation type="unfinished"></translation>
+    </message>
 </context>
 <context>
     <name>Intro</name>
@@ -2888,7 +2923,7 @@
 <context>
     <name>ShutdownWindow</name>
     <message>
-        <location filename="../utilitydialog.cpp" line="+96"/>
+        <location filename="../utilitydialog.cpp" line="+78"/>
         <source>Bitcoin Core is shutting down...</source>
         <translation type="unfinished"></translation>
     </message>

src/qt/utilitydialog.cpp

@@ -75,16 +75,16 @@ HelpMessageDialog::HelpMessageDialog(QWidget *parent, bool about) :
 
         std::string strUsage = HelpMessage(HMM_BITCOIN_QT);
         const bool showDebug = GetBoolArg("-help-debug", false);
-        strUsage += HelpMessageGroup(_("UI Options:"));
+        strUsage += HelpMessageGroup(tr("UI Options:").toStdString());
         if (showDebug) {
             strUsage += HelpMessageOpt("-allowselfsignedrootcertificates", strprintf("Allow self signed root certificates (default: %u)", DEFAULT_SELFSIGNED_ROOTCERTS));
         }
-        strUsage += HelpMessageOpt("-choosedatadir", strprintf(_("Choose data directory on startup (default: %u)"), DEFAULT_CHOOSE_DATADIR));
-        strUsage += HelpMessageOpt("-lang=<lang>", _("Set language, for example \"de_DE\" (default: system locale)"));
-        strUsage += HelpMessageOpt("-min", _("Start minimized"));
-        strUsage += HelpMessageOpt("-rootcertificates=<file>", _("Set SSL root certificates for payment request (default: -system-)"));
-        strUsage += HelpMessageOpt("-splash", strprintf(_("Show splash screen on startup (default: %u)"), DEFAULT_SPLASHSCREEN));
-        strUsage += HelpMessageOpt("-resetguisettings", _("Reset all settings changes made over the GUI"));
+        strUsage += HelpMessageOpt("-choosedatadir", strprintf(tr("Choose data directory on startup (default: %u)").toStdString(), DEFAULT_CHOOSE_DATADIR));
+        strUsage += HelpMessageOpt("-lang=<lang>", tr("Set language, for example \"de_DE\" (default: system locale)").toStdString());
+        strUsage += HelpMessageOpt("-min", tr("Start minimized").toStdString());
+        strUsage += HelpMessageOpt("-rootcertificates=<file>", tr("Set SSL root certificates for payment request (default: -system-)").toStdString());
+        strUsage += HelpMessageOpt("-splash", strprintf(tr("Show splash screen on startup (default: %u)").toStdString(), DEFAULT_SPLASHSCREEN));
+        strUsage += HelpMessageOpt("-resetguisettings", tr("Reset all settings changes made over the GUI").toStdString());
         if (showDebug) {
             strUsage += HelpMessageOpt("-uiplatform", strprintf("Select platform to customize UI for (one of windows, macosx, other; default: %s)", BitcoinGUI::DEFAULT_UIPLATFORM));
         }