message: Remove check for lookbehind support in regex
  We no longer support VSCode versions older than 1.37.0, and this was fixed in 1.31.0
diff: @@ -589,27 +589,18 @@ export class Position extends vscode.Position {
  const escaped = characterSet && _.escapeRegExp(characterSet).replace(/-/g, '\\-');
  const segments: string[] = [];
  - // old versions of VSCode before 1.31 will crash when trying to parse a regex with a lookbehind
  - let supportsLookbehind = true;
  - try {
  - // tslint:disable-next-line
  - new RegExp('(<=x)');
  - } catch {
  - supportsLookbehind = false;
  - }
  -
  // prettier-ignore
  const firstSegment =
  '(' + // OPEN: group for matching camel case words
  `[^\\s${escaped}]` + // words can start with any word character
  '(?:' + // OPEN: group for characters after initial char
  - `(?:${supportsLookbehind ? '(?<=[A-Z_])' : ''}` + // If first char was a capital
  + `(?:(?<=[A-Z_])` + // If first char was a capital
  `[A-Z](?=[\\sA-Z0-9${escaped}_]))+` + // the word can continue with all caps
  '|' + // OR
  - `(?:${supportsLookbehind ? '(?<=[0-9_])' : ''}` + // If first char was a digit
  + `(?:(?<=[0-9_])` + // If first char was a digit
  `[0-9](?=[\\sA-Z0-9${escaped}_]))+` + // the word can continue with all digits
  '|' + // OR
  - `(?:${supportsLookbehind ? '(?<=[_])' : ''}` + // If first char was an underscore
  + `(?:(?<=[_])` + // If first char was an underscore
  `[_](?=[\\s${escaped}_]))+` + // the word can continue with all underscores
  '|' + // OR
  `[^\\sA-Z0-9${escaped}_]*` + // Continue with regular characters
  