Syntax highlighting and recognition of code snippets

[jbm950]

Some places code syntax highlighting is not picked up and code is not runnable with SymPy Live. The syntax highlighting might be traced back to whether or not a space is used before a double colon when declaring code blocks as can be seen on this page. Other places SymPy Live recognizes code blocks unless it is only a single line of code which are not "runable" as can be seen on this page

[jbm950]

Was looked at and discussed in PR #11117 in the sympy repository