Change style of h4 to pop less out

The h4 style dominated h3 which was problematic for larger
bodies of text. This PR proposes a slightly smaller font-size
and not using bold-face. It also adjusts the margins slightly
to be closer to the textbody.

The style is only rarely used and the effect can be observed
on the following page:

   /overviews/core/actors.html

Author: b-studios

_sass/layout/type-md.scss

@@ -43,10 +43,10 @@
 
     h4,
     h5 {
-        font-size: 1.063rem;
+        font-size: 1.0rem;
         font-family: $base-font-family;
         text-transform: uppercase;
-        font-weight: $font-bold;
+        font-weight: $font-regular;
     }
 }
 
@@ -74,13 +74,12 @@
 .text-step {
     h2 {
         margin-bottom: 24px;
-
+    }
+    h3 {
+        margin-bottom: 0.5rem;
     }
 
     blockquote,
-    h3,
-    h4,
-    h5,
     img,
     p,
     pre,
@@ -89,6 +88,10 @@
         margin-bottom: 18px;
     }
 
+    h4, h5 {
+        margin-bottom: 0.5rem;
+    }
+
     ol,
     ul {
         padding-left: 18px;