Fix delimiter for mintinline when braces are in it.

[QuLogic]

If an inline code section contains an unmatched brace, then using braces as the \mintinline delimiter breaks. The inline section will extend to the next matching brace instead.

\mintinline can use any other character for a delimiter, so try to switch to something else when braces are in the text.

This also includes a fix for an invalid escape sequence.

[ricopicone]

Fwiw, I support this PR. Ran into this issue today.