message: Fix matching empheq
  Related to the discussion in
diff: ]
  },
  {
  - "begin": "(\\\\begin\\{empheq\\}(?:\\[.*\\])?)",
  + "begin": "(?:\\s*)(\\\\begin\\{empheq\\}(?:\\[.*\\])?)",
  "captures": {
  "1": {
  "patterns": [
  }
  },
  "contentName": "meta.math.block.latex support.class.math.block.environment.latex",
  - "end": "(\\\\end\\{empheq\\})",
  + "end": "(?:\\s*)(\\\\end\\{empheq\\})",
  "name": "meta.function.environment.math.latex",
  "patterns": [
  {
  