Add ability to use NewLines ("\r\n"/Environment.NewLine) in AddParagraph, AddText

[PrzemyslawKlys]

This PR adds the ability to create line breaks using \n, \r\n or Environment.NewLine

var test = document.AddParagraph("TestMe").AddText("\nFirst line\r\nAnd more " + Environment.NewLine + "in new line\r\n");

Is exactly the same as using it in explicit way:

var  test = document.AddParagraph("TestMe").AddBreak().AddText("First line").AddBreak().AddText("And more ").AddBreak().AddText("in new line").AddBreak();

Keep in mind that doing document.Paragraphs[0].Text = "\nFirst line\r\nAnd more " + Environment.NewLine + "in new line\r\n"); doesn't do anything for the Breaks(). I believe that using Text property on paragraph explicitly that would create multiple WordParagraphs from a simple Set should not do that.

Full example:

public static void Example_BasicWordWithNewLines(string folderPath, bool openWord) {
    Console.WriteLine("[*] Creating standard document with different default style (PL)");
    string filePath = System.IO.Path.Combine(folderPath, "BasicWordWithTabs.docx");
    using (WordDocument document = WordDocument.Create(filePath)) {

        var paragraph1 = document.AddParagraph("This is a start");

        Console.WriteLine("Paragraph count (expected 1): " + document.Paragraphs.Count);

        var paragraph2 = document.AddParagraph("This is a start \t\t And more");

        Console.WriteLine("Paragraph count (expected 2): " + document.Paragraphs.Count);

        var paragraph3 = document.AddParagraph("This is a start \t\t And more");
        paragraph3.Underline = UnderlineValues.DashLong;

        Console.WriteLine("Paragraph count (expected 3): " + document.Paragraphs.Count);

        // now we will try to add new line characters, that will force the paragraph to be split into pieces
        // following will split the paragraph into 3 paragraphs - 2 paragraphs with Text, and one Break()
        var paragraph4 = document.AddParagraph("First line\r\nAnd more in new line");

        Console.WriteLine("Paragraph count (expected 6): " + document.Paragraphs.Count);

        // following will split the paragraph into 3 paragraphs - 2 paragraphs with Text, and one Break()
        var paragraph6 = document.AddParagraph("First line\nnd more in new line");

        Console.WriteLine("Paragraph count (expected 9): " + document.Paragraphs.Count);

        // following will split the paragraph into 3 paragraphs - 2 paragraphs with Text, and one Break()
        var paragraph7 = document.AddParagraph("First line" + Environment.NewLine + "And more in new line");

        Console.WriteLine("Paragraph count (expected 12): " + document.Paragraphs.Count);

        // following will split the paragraph into 7 paragraphs - 3 paragraphs with Text, and 4 paragraphs with Break()
        // additionally there's one paragraph at start
        var paragraph8 = document.AddParagraph("TestMe").AddText("\nFirst line\r\nAnd more " + Environment.NewLine + "in new line\r\n");

        Console.WriteLine("Paragraph count (expected 20): " + document.Paragraphs.Count);

        // following will split the paragraph into 7 paragraphs - 3 paragraphs with Text, and 4 paragraphs with Break()
        // additionally there's one paragraph at start
        // it's the same as above but written in a direct way. All above methods are just shortcuts for this
        var paragraph9 = document.AddParagraph("TestMe").AddBreak().AddText("First line").AddBreak().AddText("And more ").AddBreak().AddText("in new line").AddBreak();

        Console.WriteLine("Paragraph count (expected 28): " + document.Paragraphs.Count);

        document.Save(openWord);
    }
}