Bug 1932926 - Fix stylelint issues. r=arschmitz,aleca

Differential Revision: https://phabricator.services.mozilla.com/D229949

--HG--
extra : moz-landing-system : lando

.stylelintrc.js

@@ -232,5 +232,16 @@ module.exports = {
         ignorePseudoClasses: ["popover-open"],
       },
     ],
+    "selector-pseudo-element-no-unknown": [
+      true,
+      {
+        ignorePseudoElements: ["slider-track", "slider-fill", "slider-thumb"],
+      },
+    ],
+
+    "media-feature-name-no-unknown": true,
+    "media-feature-name-value-no-unknown": true,
+    // Disabled for -moz-bool-pref
+    "media-query-no-invalid": null,
   },
 };

mail/themes/shared/mail/customizableshortcuts/shortcuts-container.css

@@ -15,7 +15,6 @@ dialog {
   height: 400px;
   overflow: hidden;
   padding: 0;
-  box-shadow: none;
   border: none;
   border-radius: 6px;
   background-color: var(--color-neutral-base);

mail/themes/shared/mail/icons.css

@@ -18,11 +18,9 @@
   --icon-sparkle-star-sm: url("chrome://messenger/skin/icons/sm/sparkle-star.svg");
   --icon-upload-sm: url("chrome://messenger/skin/icons/sm/upload.svg");
   --icon-mobile-export-sm: url("chrome://messenger/skin/icons/sm/mobile-export.svg");
-  --icon-mobile-export-sm: url("chrome://messenger/skin/icons/sm/mobile-export.svg");
 
   /* LG - 24x24px icons */
   --icon-mobile-export-lg: url("chrome://messenger/skin/icons/lg/mobile-export.svg");
-  --icon-mobile-export-lg: url("chrome://messenger/skin/icons/lg/mobile-export.svg");
 
   --icon-account-settings: url("chrome://messenger/skin/icons/new/compact/account-settings.svg");
   --icon-add: url("chrome://messenger/skin/icons/new/compact/add.svg");