Tweak alignment of ionicons

This somehow works even though ion-icon is like an undefined HTML tag.

agaric/sass/agaric/_component.agaricons.scss

@@ -226,3 +226,9 @@ $agaricon-path: 'fonts' !default;
 .agc-mushroom::before {
   content: "\e031";
 }
+
+/* Extra styling for Ionicons */
+
+ion-icon {
+  vertical-align: text-bottom;
+}