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.

blorg/testdata/public/about.html

@@ -24,13 +24,10 @@
       <ul class="tags">
         
       </ul>
-      <h1 class="title"><p>
-About
-</p>
+      <h1 class="title"><p>About</p>
 </h1>
 <p>
-and some content
-</p>
+and some content</p>
 
     </div>
   </body>

blorg/testdata/public/post.html

@@ -24,9 +24,7 @@
       <ul class="tags">
         
       </ul>
-      <h1 class="title"><p>
-some post
-</p>
+      <h1 class="title"><p>some post</p>
 </h1>
 
     </div>