Refactoring: fix import buttons (WIP)

UI/Base/BackButton.svelte

@@ -1,6 +1,7 @@
 <script lang="ts">
     /**
      * Wrapper around 'subtleButton' with an arrow pointing to the right
+     * See also: NextButton
      */
     import SubtleButton from "./SubtleButton.svelte";
     import {ChevronLeftIcon} from "@rgossiaux/svelte-heroicons/solid";
@@ -12,5 +13,5 @@
 
 <SubtleButton on:click={() => dispatch("click")} options={{extraClasses:clss+ " flex items-center"}}>
     <ChevronLeftIcon class="w-12 h-12" slot="image"/>
-    <slot name="message" slot="message"/>
+    <slot slot="message"/>
 </SubtleButton>

UI/Base/MapControlButton.svelte

@@ -5,9 +5,10 @@
    * A round button with an icon and possible a small text, which hovers above the map
    */
    const dispatch = createEventDispatcher()
+  export let cls = ""
 </script>
 
 
-<button on:click={e => dispatch("click", e)} class="rounded-full h-fit w-fit m-0.5 md:m-1 p-0.5 sm:p-1 pointer-events-auto">
+<button on:click={e => dispatch("click", e)} class={"rounded-full h-fit w-fit m-0.5 md:m-1 p-0.5 sm:p-1 pointer-events-auto "+cls} >
   <slot/>
 </button>

UI/Base/NextButton.svelte

@@ -1,6 +1,7 @@
 <script lang="ts">
     /**
      * Wrapper around 'subtleButton' with an arrow pointing to the right
+     * See also: BackButton
      */
     import SubtleButton from "./SubtleButton.svelte";
     import {ChevronRightIcon} from "@rgossiaux/svelte-heroicons/solid";