`\enclose{circle}` example in documentation doesn't work as written

[hbghlyj]

The documentation page MathJax TeX Enclose Extension demonstrates the example \enclose{circle}[mathcolor="red"]{x}. However, this example doesn't work as intended. Instead, changing it to \enclose{circle}[mathcolor=red]{x} works correctly.

This discrepancy may cause confusion for users. Please update the documentation to reflect the correct syntax.