Add AnchorJS logic for header links (#10155)

* Add AnchorJS JavaScript

* Remove existing inpage_heading logic

* Remove underline from anchor tags

* Use single icon and add touch visibility

* Use paragraph link icon for AnchorJS

* Update Sass to use code formatting in docsContent headers

* Update header size coverage to H3-H6

assets/sass/_base.sass

@@ -800,8 +800,6 @@ dd
 	&:after
 		transform: rotate(-45deg)
 
-
-
 #docsContent
 	position: relative
 	float: right
@@ -895,7 +893,6 @@ dd
 		overflow-x: auto
 
 	h1 code, h2 code, h3 code, h4 code, h5 code, h6 code
-		font-family: inherit
 		font-size: inherit
 		background-color: transparent
 
@@ -999,10 +996,6 @@ dd
 	img
 		max-width: 100%
 
-	a
-		//font-weight: 700
-		text-decoration: underline
-
 	#TableOfContents > ul > li { list-style: none; }
 	#TableOfContents
 		ul, li