DolphinQt: Add i18n comment for "Keep addresses where value in memory"

This string is extremely likely to be mistranslated without the
proper context. Actually, it's probably impossible to translate
this string in a good way to some languages, but I'm not sure how
to solve that. Let's at least add an i18 comment for now.

Source/Core/DolphinQt/CheatSearchWidget.cpp

@@ -159,6 +159,11 @@ void CheatSearchWidget::CreateWidgets()
 
   auto* value_layout = new QHBoxLayout();
 
+  // i18n: This label is followed by a dropdown where the user can select things like "is equal to"
+  // or "is less than or equal to", followed by another dropdown where the user can select "any
+  // value", "last value", or "this value:". These three UI elements are intended to form a sentence
+  // together. Because the UI elements can't be reordered by a translation, you may have to give
+  // up on the idea of having them form a sentence depending on the grammar of your target language.
   auto* instructions_label = new QLabel(tr("Keep addresses where value in memory"));
   value_layout->addWidget(instructions_label);