message: Support \def in addition to \newcommand in mathjax preview
diff: @@ -115,7 +115,7 @@ export class HoverProvider implements vscode.HoverProvider {
  }
  private findNewCommand(content: string) : string {
  - const regex = /(\\(?:(?:re)?new|provide)command(\*)?(?:\[[^\[\]\{\}]*\])*{.*})/gm
  + const regex = /(\\(?:(?:(?:re)?new|provide)command(\*)?(?:\[[^\[\]\{\}]*\])*{.*})|\\(?:def\\[a-zA-Z]+(?:#[0-9])*{.*}))/gm
  const commands: string[] = []
  let result
  do {
  