optimize figure bottom margin (pydata#1749)

* figure bottom margin

Avoid multiple margin-bottom by `p` and `figure`, that result in too wide a bottom margin.

* Update _figures.scss

* Only adjust margins at top and bottom of figcaption

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Co-authored-by: gabalafou <[email protected]>

Author: berlin2123

src/pydata_sphinx_theme/assets/styles/content/_figures.scss

@@ -15,6 +15,12 @@ figure {
     color: var(--pst-color-text-muted);
     margin-left: auto;
     margin-right: auto;
+    margin-top: 0.3rem;
+
+    & > p:last-child {
+      // Don't add extra margin to already existing figure bottom margin
+      margin-bottom: 0;
+    }
 
     table.table {
       width: fit-content;