Add explainer about fast sync to file provider settings

Signed-off-by: Claudio Cambra <claudio.cambra@nextcloud.com>

src/gui/macOS/ui/FileProviderFastEnumerationSettings.qml

@@ -30,7 +30,7 @@ Column {
     property bool fastEnumerationSet: false
     property bool fastEnumerationEnabled: true
 
-    padding: 0
+    spacing: 0
 
     CheckBox {
         id: fastEnumerationEnabledCheckBox
@@ -39,4 +39,21 @@ Column {
         checked: root.fastEnumerationEnabled
         onClicked: root.fastEnumerationEnabledToggled(checked)
     }
+
+    EnforcedPlainTextLabel {
+        id: fastEnumerationDescription
+        background: Rectangle {
+            color: Style.infoBoxBackgroundColor
+            border.width: Style.infoBoxBorderWidth
+            border.color: Style.infoBoxBorderColor
+            radius: Style.slightlyRoundedButtonRadius
+        }
+        width: parent.width
+        padding: Style.smallSpacing
+        text: qsTr("Fast sync will only sync changes in files and folders within folders that have been explored. " +
+                    "This can significantly increase responsiveness on initial configuration of virtual files. " +
+                    "However, it will cause redundant downloads of files moved to an unexplored folder. ")
+        wrapMode: Text.Wrap
+        visible: fastEnumerationEnabled
+    }
 }

theme/Style/Style.qml

@@ -29,6 +29,11 @@ QtObject {
     readonly property color errorBoxBackgroundColor: Qt.rgba(0.89, 0.18, 0.18, 1)
     readonly property int errorBoxStripeWidth: 4
 
+    // InfoBox colors
+    readonly property color infoBoxBackgroundColor: Qt.rgba(0, 0.51, 0.79, 0.1)
+    readonly property int infoBoxBorderWidth: 1
+    readonly property color infoBoxBorderColor: Qt.rgba(0, 0.51, 0.79, 1)
+
     // Fonts
     // We are using pixel size because this is cross platform comparable, point size isn't
     readonly property int topLinePixelSize: pixelSize