Repository: pypa/readme_renderer (language: python)

Issue:
Recent upgrade of docutils seems to have broken formatting of RestructuredText descriptions
**Description**
Included graphics now have an un-rendered `<figure class="align-center">` start tag and end tag `</figure>`
For an example see https://pypi.org/project/plot-antenna/1.0/
This worked previously for the same ReST.

When including citation references, the citation at the end now has a newline after the citation mark and no hanging indent is used. An example is also under the link above.

Note for my Nikola Blog (also ReST based) I had to include the following CSS for correctly formatting citations:

```
aside.footnote p {
    display: inline;
}

aside.footnote {
    padding-left: 2em;
    text-indent: -2em;
}
```

**Expected behavior**
Github displays the same ReST fine: https://github.com/schlatterbeck/plot-antenna

**To Reproduce**
See https://pypi.org/project/plot-antenna/1.0/
source of is the README for https://github.com/schlatterbeck/plot-antenna

**My Platform**
Firefox browser on Debian Bullseye


Discussion / hints:

Fix patch:
diff --git a/readme_renderer/clean.py b/readme_renderer/clean.py
index 386e684..f610954 100644
--- a/readme_renderer/clean.py
+++ b/readme_renderer/clean.py
@@ -30,7 +30,7 @@
     "br", "caption", "cite", "col", "colgroup", "dd", "del", "details", "div",
     "dl", "dt", "h1", "h2", "h3", "h4", "h5", "h6", "hr", "img", "p", "pre",
     "span", "sub", "summary", "sup", "table", "tbody", "td", "th", "thead",
-    "tr", "tt", "kbd", "var", "input", "section", "aside", "nav", "s",
+    "tr", "tt", "kbd", "var", "input", "section", "aside", "nav", "s", "figure",
 ]
 
 ALLOWED_ATTRIBUTES = {
@@ -64,6 +64,7 @@
     "dt": ["class"],
     "ul": ["class"],
     "nav": ["class"],
+    "figure": ["class"],
 }
 
 


Test patch:
diff --git a/tests/fixtures/test_rst_figure.html b/tests/fixtures/test_rst_figure.html
new file mode 100644
index 0000000..0975d30
--- /dev/null
+++ b/tests/fixtures/test_rst_figure.html
@@ -0,0 +1,3 @@
+<figure class="align-center">
+<img alt="https://raw.githubusercontent.com/schlatterbeck/plot-antenna/master/test/12-el-azimuth.png" src="https://raw.githubusercontent.com/schlatterbeck/plot-antenna/master/test/12-el-azimuth.png">
+</figure>
diff --git a/tests/fixtures/test_rst_figure.rst b/tests/fixtures/test_rst_figure.rst
new file mode 100644
index 0000000..648f161
--- /dev/null
+++ b/tests/fixtures/test_rst_figure.rst
@@ -0,0 +1,2 @@
+.. figure:: https://raw.githubusercontent.com/schlatterbeck/plot-antenna/master/test/12-el-azimuth.png
+    :align: center