Add support for <style> and <script> inside <svg>

[takenspc]

Currently, the contents of <style> and <script> inside are not highlighted.

To make the contents of <style> and <script> inside highlighted, this PR

1. moves html's <style> and <script> definitions into repository
2. makes html include repository's <style> and <script> definitions
3. makes svg include repository's <style> and <script> definitions