Allow picking multiple files to upload

resources/langs/nheko_en.ts

@@ -1395,8 +1395,8 @@ You may optionally provide a reason for others to accept your knock:</translatio
     <name>InputBar</name>
     <message>
         <location filename="../../src/timeline/InputBar.cpp" line="+372"/>
-        <source>Select a file</source>
+        <source>Select file(s)</source>
-        <translation>Select a file</translation>
+        <translation>Select file(s)</translation>
     </message>
     <message>
         <location line="+0"/>

src/timeline/InputBar.cpp

@@ -417,13 +417,14 @@ void
 InputBar::openFileSelection()
 {
     const QString homeFolder = QStandardPaths::writableLocation(QStandardPaths::HomeLocation);
-    const auto fileName =
+    const QStringList fileNames =
-      QFileDialog::getOpenFileName(nullptr, tr("Select a file"), homeFolder, tr("All Files (*)"));
+      QFileDialog::getOpenFileNames(nullptr, tr("Select file(s)"), homeFolder, tr("All Files (*)"));
 
-    if (fileName.isEmpty())
+    if (fileNames.isEmpty())
         return;
 
-    startUploadFromPath(fileName);
+    for (const auto &fileName : fileNames)
+        startUploadFromPath(fileName);
 }
 
 QString