News RSS feed entries contain no useful text

https://www.preview.boost.org/feed/news.rss

Each news entry in the News RSS feed contains text of the form "External link to .", which is useless. RSS entries are supposed to contain the actual content of the news entry, possibly reduced, if the article is lengthy. The URL to the full article is already included in the `html/head/base` tag and is accordingly rendered by Thunderbird in the entry description.

For example, here is one of the entries:

```
From - Thu, 23 May 2024 00:00:00 +0000
X-Mozilla-Status: 0041
X-Mozilla-Status2: 00000000
X-Mozilla-Keys:
Received: by localhost; Thu, 6 Jun 2024 14:05:54 +0300
Date: Thu, 23 May 2024 00:00:00 +0000
Message-Id:
From:
MIME-Version: 1.0
Subject: WG21, Boost, and the Ways of Standardization
Content-Transfer-Encoding: 8bit
Content-Base: http://www.boost.io/news/entry/wg21-boost-and-the-ways-of-standardization/
Content-Type: text/html; charset=UTF-8

WG21, Boost, and the Ways of Standardization



External link to https://www.reddit.com/r/cpp/comments/1cyxh9n/wg21_boost_and_the_ways_of_standardization/.

```

Here is how it looks in Thunderbird:


The main benefit of using RSS is not having to browse through a dozen of websites for news articles and having all or most of the information readily available in the news reader app. Posting news entries with a single URL in the body counters that.

BTW, following the link shows this page, which is also not useful and poorly formatted:


Note that the URL is not highlighted as clickable.

Start by opening https://www.preview.boost.org/feed/news.rss and inspecting how news entries are generated; reproduce the description in Thunderbird or another RSS reader. Trace the feed output back to its entry-generation code, then verify that descriptions contain useful article content while retaining the full-article link.

Written by the indexing model from the issue text.