Expose "getNewLineCharacter" function

Suggestion

Make ts.getNewLineCharacter public

Use Cases

This is useful if developers create their own FormatDiagnosticsHost, but don't want to implement the logic to determine the newLine string based on the newLine compiler option.

Examples

    const formatHost: ts.FormatDiagnosticsHost = {
      getCurrentDirectory: () => projectDir || ts.sys.getCurrentDirectory(),
      getCanonicalFileName: fileName => fileName,
      getNewLine: () => ts.getNewLineCharacter(formatOptions)
    };

Start by locating the existing ts.getNewLineCharacter implementation and its public compiler API declarations. Read how FormatDiagnosticsHost and the newLine compiler option are currently exposed, then make the function publicly callable and verify that the example use case can obtain the selected newline character.