Update syntax highlighting library

Assets/css/prism.css

@@ -1,5 +1,5 @@
-/* PrismJS 1.15.0
-https://prismjs.com/download.html#themes=prism-okaidia&languages=markup+css+clike+javascript+abap+actionscript+ada+apacheconf+apl+applescript+c+arff+asciidoc+asm6502+csharp+autohotkey+autoit+bash+basic+batch+bison+brainfuck+bro+cpp+aspnet+arduino+coffeescript+clojure+ruby+csp+css-extras+d+dart+diff+django+docker+eiffel+elixir+elm+markup-templating+erlang+fsharp+flow+fortran+gedcom+gherkin+git+glsl+go+graphql+groovy+haml+handlebars+haskell+haxe+http+hpkp+hsts+ichigojam+icon+inform7+ini+io+j+java+jolie+json+julia+keyman+kotlin+latex+less+liquid+lisp+livescript+lolcode+lua+makefile+markdown+erb+matlab+mel+mizar+monkey+n4js+nasm+nginx+nim+nix+nsis+objectivec+ocaml+opencl+oz+parigp+parser+pascal+perl+php+php-extras+sql+powershell+processing+prolog+properties+protobuf+pug+puppet+pure+python+q+qore+r+jsx+typescript+renpy+reason+rest+rip+roboconf+crystal+rust+sas+sass+scss+scala+scheme+smalltalk+smarty+plsql+soy+stylus+swift+yaml+tcl+textile+tt2+twig+tsx+vbnet+velocity+verilog+vhdl+vim+visual-basic+wasm+wiki+xeora+xojo+xquery+tap&plugins=line-numbers+toolbar+show-language+copy-to-clipboard */
+/* PrismJS 1.20.0
+https://prismjs.com/download.html#themes=prism-okaidia&languages=markup+css+clike+javascript+abap+abnf+actionscript+ada+al+antlr4+apacheconf+apl+applescript+aql+arduino+arff+asciidoc+asm6502+aspnet+autohotkey+autoit+bash+basic+batch+bbcode+bison+bnf+brainfuck+brightscript+bro+c+concurnas+csharp+cpp+cil+coffeescript+cmake+clojure+crystal+csp+css-extras+d+dart+dax+diff+django+dns-zone-file+docker+ebnf+eiffel+ejs+elixir+elm+etlua+erb+erlang+excel-formula+fsharp+factor+firestore-security-rules+flow+fortran+ftl+gcode+gdscript+gedcom+gherkin+git+glsl+gml+go+graphql+groovy+haml+handlebars+haskell+haxe+hcl+hlsl+http+hpkp+hsts+ichigojam+icon+iecst+inform7+ini+io+j+java+javadoc+javadoclike+javastacktrace+jolie+jq+jsdoc+js-extras+js-templates+json+jsonp+json5+julia+keyman+kotlin+latex+latte+less+lilypond+liquid+lisp+livescript+llvm+lolcode+lua+makefile+markdown+markup-templating+matlab+mel+mizar+monkey+moonscript+n1ql+n4js+nand2tetris-hdl+nasm+neon+nginx+nim+nix+nsis+objectivec+ocaml+opencl+oz+parigp+parser+pascal+pascaligo+pcaxis+peoplecode+perl+php+phpdoc+php-extras+plsql+powerquery+powershell+processing+prolog+properties+protobuf+pug+puppet+pure+purebasic+python+q+qml+qore+r+racket+jsx+tsx+renpy+reason+regex+rest+rip+roboconf+robotframework+ruby+rust+sas+sass+scss+scala+scheme+shell-session+smalltalk+smarty+solidity+solution-file+soy+sparql+splunk-spl+sqf+sql+stylus+swift+tap+tcl+textile+toml+tt2+turtle+twig+typescript+t4-cs+t4-vb+t4-templating+unrealscript+vala+vbnet+velocity+verilog+vhdl+vim+visual-basic+warpscript+wasm+wiki+xeora+xml-doc+xojo+xquery+yaml+zig&plugins=show-language+toolbar+copy-to-clipboard */
 /**
  * okaidia theme for JavaScript, CSS and HTML
  * Loosely based on Monokai textmate theme by http://www.monokai.nl/
@@ -12,6 +12,7 @@ pre[class*="language-"] {
 	background: none;
 	text-shadow: 0 1px rgba(0, 0, 0, 0.3);
 	font-family: Consolas, Monaco, 'Andale Mono', 'Ubuntu Mono', monospace;
+	font-size: 1em;
 	text-align: left;
 	white-space: pre;
 	word-spacing: normal;
@@ -60,7 +61,7 @@ pre[class*="language-"] {
 	color: #f8f8f2;
 }
 
-.namespace {
+.token.namespace {
 	opacity: .7;
 }
 
@@ -123,48 +124,6 @@ pre[class*="language-"] {
 	cursor: help;
 }
 
-pre[class*="language-"].line-numbers {
-	position: relative;
-	padding-left: 3.8em;
-	counter-reset: linenumber;
-}
-
-pre[class*="language-"].line-numbers > code {
-	position: relative;
-	white-space: inherit;
-}
-
-.line-numbers .line-numbers-rows {
-	position: absolute;
-	pointer-events: none;
-	top: 0;
-	font-size: 100%;
-	left: -3.8em;
-	width: 3em; /* works for line-numbers below 1000 lines */
-	letter-spacing: -1px;
-	border-right: 1px solid #999;
-
-	-webkit-user-select: none;
-	-moz-user-select: none;
-	-ms-user-select: none;
-	user-select: none;
-
-}
-
-	.line-numbers-rows > span {
-		pointer-events: none;
-		display: block;
-		counter-increment: linenumber;
-	}
-
-		.line-numbers-rows > span:before {
-			content: counter(linenumber);
-			color: #999;
-			display: block;
-			padding-right: 0.8em;
-			text-align: right;
-		}
-
 div.code-toolbar {
 	position: relative;
 }
@@ -181,6 +140,12 @@ div.code-toolbar:hover > .toolbar {
 	opacity: 1;
 }
 
+/* Separate line b/c rules are thrown out if selector is invalid.
+   IE11 and old Edge versions don't support :focus-within. */
+div.code-toolbar:focus-within > .toolbar {
+	opacity: 1;
+}
+
 div.code-toolbar > .toolbar .toolbar-item {
 	display: inline-block;
 }