/* The first indentation that doesn't match the initial
* indentation of the paragraph we justify. This is put at
* the beginning of every line broken off the first
- * justified line of the paragraph. */
+ * justified line of the paragraph. (Note that this works
+ * because a paragraph can only contain two indentations at
+ * most: the initial one, and a different one starting on a
+ * line after the first. See the comment at begpar() for
+ * more about when a line is part of a paragraph.) */
/* Find the first line of the paragraph to be justified. That
* is the start of this paragraph if we're in one, or the start