html: Remove cosmetic whitespace inside p tags

All tags are put on a line by themselves to help with visual
diffing. Apparently this extra cosmetic whitespace causes problems inside p
tags for ppl who want to use `white-space: pre`. Not much hurt for visual
diffing in removing cosmetic whitespace for just p tags and can't think of
anything that would break because of this right now. So let's do it and wait
for things to break.

org/html_writer.go

@@ -411,11 +411,8 @@ func (w *HTMLWriter) WriteParagraph(p Paragraph) {
 		return
 	}
 	w.WriteString("<p>")
-	if _, ok := p.Children[0].(LineBreak); !ok {
-		w.WriteString("\n")
-	}
 	WriteNodes(w, p.Children...)
-	w.WriteString("\n</p>\n")
+	w.WriteString("</p>\n")
 }
 
 func (w *HTMLWriter) WriteExample(e Example) {