[core] Fix Converting of HTML to Plain Text in Description (#96)

This commit fixes the conversion of HTML to plain text in the
description for an item. Until now it could happen, that the there was
no whitespace between some words after the conversion. This is now fixed
so that there is always a whitespace between words in the plain text.

app/lib/widgets/item/details/utils/item_description.dart

@@ -158,7 +158,9 @@ class ItemDescription extends StatelessWidget {
     if (sourceFormat == DescriptionFormat.html &&
         tagetFormat == DescriptionFormat.plain) {
       return _buildPlain(
-        itemDescription!.replaceAll(RegExp(r'<[^>]*>|&[^;]+;'), ''),
+        itemDescription!
+            .replaceAll(RegExp(r'<[^>]*>|&[^;]+;'), ' ')
+            .replaceAll(RegExp('\\s+'), ' '),
       );
     }
 

app/lib/widgets/item/preview/utils/item_description.dart

@@ -125,7 +125,9 @@ class ItemDescription extends StatelessWidget {
     if (sourceFormat == DescriptionFormat.html &&
         tagetFormat == DescriptionFormat.plain) {
       return _buildPlain(
-        itemDescription!.replaceAll(RegExp(r'<[^>]*>|&[^;]+;'), ''),
+        itemDescription!
+            .replaceAll(RegExp(r'<[^>]*>|&[^;]+;'), ' ')
+            .replaceAll(RegExp('\\s+'), ' '),
       );
     }