Function isMdAsciiPunct

Markdown ASCII punctuation characters.

!, ", #, $, %, &, ', (, ), *, +, ,, -, ., /, :, ;, <, =, >, ?, @,
[, \, ], ^, _, `, {, |, }, or ~

http://spec.commonmark.org/0.15/#ascii-punctuation-character

Don't confuse with Unicode punctuation. It lacks some characters in the ASCII range.