fix(CodeBlock): Add new syntax highlighter (#682)

We had previously dropped react-syntax-highlighter due to a vulnerability. It has been several months and they have yet to fix it, though are making progress. Rehype-highlight is maintained by unified, which maintains the Markdown processor, and seems better maintained. We can swap out the highlighting style to any of these options very easily if needed as well: https://highlightjs.org/examples

Author: rebeccaalpert

jest.config.js

@@ -7,7 +7,7 @@ module.exports = {
   collectCoverage: true,
   // most of these are to fix https://github.com/remarkjs/react-markdown/issues/635
   transformIgnorePatterns: [
-    'node_modules/(?!@patternfly|@data-driven-forms|remark-gfm|react-markdown|remark-parse|devlop|hast-util-to-jsx-runtime|comma-separated-tokens|estree-util-is-identifier-name|hast-util-whitespace|property-information|space-separated-tokens|unist-util-position|vfile-message|unist-util-stringify-position|html-url-attributes|mdast-util-from-markdown|mdast-util-to-string|micromark|decode-named-character-reference|remark-rehype|mdast-util-to-hast|trim-lines|unist-util-visit|unist-util-is|unified|bail|is-plain-obj|trough|vfile|mdast-util-gfm|ccount|mdast-util-find-and-replace|escape-string-regexp|markdown-table|mdast-util-to-markdown|zwitch|longest-streak|mdast-util-phrasing)'
+    'node_modules/(?!@patternfly|@data-driven-forms|remark-gfm|react-markdown|remark-parse|devlop|hast-util-to-jsx-runtime|comma-separated-tokens|estree-util-is-identifier-name|hast-util-whitespace|property-information|space-separated-tokens|unist-util-position|vfile-message|unist-util-stringify-position|html-url-attributes|mdast-util-from-markdown|mdast-util-to-string|micromark|decode-named-character-reference|remark-rehype|mdast-util-to-hast|trim-lines|unist-util-visit|unist-util-is|unified|bail|is-plain-obj|trough|vfile|mdast-util-gfm|ccount|mdast-util-find-and-replace|escape-string-regexp|markdown-table|mdast-util-to-markdown|zwitch|longest-streak|mdast-util-phrasing|rehype-highlight)'
     // Uncomment the below line if you face any errors with jest
     // '/node_modules/(?!@redhat-cloud-services)',
   ],