fix: do not cut off bottom portion of text

Author: dajrivera

src/themes/shared/_markdown.css

@@ -248,6 +248,7 @@
     margin: 2rem 0 0.5em;
     color: var(--heading-color);
     font-weight: var(--heading-font-weight);
+    line-height: normal;
 
     /* Prevent long titles from causing horizontal scrolling */
     &[id] a {