client: mark some checkboxes to use the new style

src/public/app/widgets/type_widgets/options/appearance/electron_integration.ts

@@ -17,7 +17,7 @@ const TPL = `
     <hr />
 
     <div class="side-checkbox">
-        <label class="form-check">
+        <label class="form-check tn-checkbox">
             <input type="checkbox" class="native-title-bar form-check-input" />
             <strong>${t("electron_integration.native-title-bar")}</strong>
             <p>${t("electron_integration.native-title-bar-description")}</p>
@@ -25,7 +25,7 @@ const TPL = `
     </div>
 
     <div class="side-checkbox">
-        <label class="form-check">
+        <label class="form-check tn-checkbox">
             <input type="checkbox" class="background-effects form-check-input" />
             <strong>${t("electron_integration.background-effects")}</strong>
             <p>${t("electron_integration.background-effects-description")}</p>

src/public/app/widgets/type_widgets/options/other/tray.ts

@@ -7,7 +7,7 @@ const TPL = `
 <div class="options-section">
     <h4>${t("tray.title")}</h4>
 
-    <label>
+    <label class="tn-checkbox">
         <input type="checkbox" class="tray-enabled">
         ${t("tray.enable_tray")}
     </label>

src/public/app/widgets/type_widgets/options/spellcheck.ts

@@ -17,7 +17,7 @@ const TPL_ELECTRON = `
 
     <p>${t("spellcheck.restart-required")}</p>
 
-    <label>
+    <label class="tn-checkbox">
         <input type="checkbox" class="spell-check-enabled">
         ${t("spellcheck.enable")}
     </label>