subject wrapping bug after display-toggle-weed
After `<display-toggle-weed>`, it seems that Mutt preserves the newline characters that are present for header folding. This makes sense if the goal is to see unprocessed headers, but since the headers are decoded, there is no need to do that, and it even looks strange. For instance, if one has
```
Subject: abcde =?iso-8859-1?Q?fghijk=E9lmno?= =?iso-8859-1?Q?p?= qrs
tuvwxyzabcd
```
then one normally gets
```
Subject: abcde fghijkélmnop qrs tuvwxyzabcd
```
but after `<display-toggle-weed>`, one gets
```
Subject: abcde fghijkélmnop qrs
tuvwxyzabcd
```
issue