2.0.0

• f0e0c1c Change exports to functions that return extensions

   const tree = fromMarkdown(doc, {
  -  extensions: [math],
  -  mdastExtensions: [mathFromMarkdown]
  +  extensions: [math()],
  +  mdastExtensions: [mathFromMarkdown()]
   })
  
   ...
  
  -const out = toMarkdown(tree, {extensions: [mathToMarkdown]})
  +const out = toMarkdown(tree, {extensions: [mathToMarkdown()]})

• 31360ab Add singleDollarTextMath option