[Translations] Give translators context for separator-bearing tr() strings

Build the card menu's related card actions from complete strings with %1
placeholders instead of appending translated fragments. This also fixes
tr(cond ? "Transform into " : "Attach to "), which lupdate cannot extract:
neither string appears in cockatrice_en@source.ts, so neither was ever
translated.

Give the EDHRec tab title a %1 placeholder so French can render
"EDHRec : %1" instead of concatenating into "EDHRec :CardName".

Keep the colon in tr("Token:") and the leading space in tr(" seconds"),
since that separator is language-specific, and attach //: translator
comments so they are no longer shown out of context on Transifex.

cockatrice/src/interface/widgets/settings_page/appearance_settings_page.cpp

@@ -129,6 +129,7 @@ AppearanceSettingsPage::AppearanceSettingsPage()
     });
 
     homeTabBackgroundShuffleFrequencySpinBox.setRange(0, 3600);
+    //: Unit following a number of seconds. Keep the leading space unless your language writes number and unit flush.
     homeTabBackgroundShuffleFrequencySpinBox.setSuffix(tr(" seconds"));
     homeTabBackgroundShuffleFrequencySpinBox.setValue(settings.appearance().getHomeTabBackgroundShuffleFrequency());
     connect(&homeTabBackgroundShuffleFrequencySpinBox, qOverload<int>(&QSpinBox::valueChanged), &settings.appearance(),