// Package notation adds the inline marks CommonMark has no syntax for: subscript, superscript,
// strikethrough and highlight.
//
// Every one is a delimiter pair around text, so they are one mechanism rather than four (ADR-0061). The
// tilde carries two meanings by run length — `~2~` subscripts and `~~struck~~` strikes — which is Pandoc's
// rule and the reason strikethrough lives here rather than in goldmark's own extension: sharing a byte
// between two features is how they break each other.
package notation