Add docx comment support

[9rnsr]

This is my first contribution to NPOI. I'm not sure about any contributing process that I should follow, please give me advice.

When I've tried to modify comments in docx file, the feature was not yet implemented. Porting code from POI was not so difficult.

[tonyqus]

Thank you for your contribution.

I notice that there is no real code change but formatting changes and remove namespaces in the following files
XWPFDocument.cs
XWPFRelation.cs

Can you revert any changes about formatting so that it's easy for me to focus on reviewing the real code changes.

Btw, which version of POI do you reference?

[9rnsr]

Thank you for your quick reply!

I ported real code changes from latest version POI 5.2.3.

Already the style changes has been collected into first one commit so you can see remain commits to review real changes.

(To be honest, those changes has been done by Visual Studio auto-formatting on save, so keeping styles unchanging is hard to do in my development environment. If it's really required in this project, I'll edit commits.)

[9rnsr]

@tonyqus OK, I completely removed style changes in each commits.

Now this PR contains real code changes only. Good?

[tonyqus]

LGTM

[9rnsr]

Thanks!

[tonyqus]

I tried to create a comment sample. But I cannot make it work.

XWPFParagraph paragraph = doc.CreateParagraph();
XWPFRun run = paragraph.CreateRun();
run.SetText("This is text");

var comments=doc.CreateComments();
var comment1=comments.CreateComment("0");
comment1.Author = "Tony";
comment1.Initials = "S";
comment1.Date = DateTime.Now.ToShortDateString();

var comment2=comments.CreateComment("1");
comment1.Author = "May";
var para=comment2.CreateParagraph();
var run2 = para.CreateRun();
run2.SetText("Hello World");


using (FileStream sw = File.Create("comments.docx"))
{
    doc.Write(sw);
}

I cannot see the comments in Word even if I turn "Show comments" on

Did I miss something?

[9rnsr]

It's necessary to handle underlying CT_x objects to emit comments to docx.

Reference: https://stackoverflow.com/questions/63935140/adding-comment-to-a-specific-word-or-run-in-docx-document-using-apache-poi

using (XWPFDocument doc = new XWPFDocument())
{
    var comments = doc.CreateComments();

    var comment1 = comments.CreateComment("0");
    comment1.Author = "Tony";
    comment1.Initials = "S";
    comment1.Date = DateTime.Now.ToShortDateString();

    var comment2 = comments.CreateComment("1");
    comment2.Author = "May";
    var para = comment2.CreateParagraph();
    para.CreateRun().SetText("Hello World");

    var paragraph1 = doc.CreateParagraph();
    paragraph1.CreateRun().SetText("This is ");
    paragraph1.GetCTP().AddNewCommentRangeStart().id = comment1.Id;
    paragraph1.CreateRun().SetText("1st comment");
    paragraph1.GetCTP().AddNewCommentRangeEnd().id = comment1.Id;
    paragraph1.CreateRun().SetText(" text.");
    paragraph1.GetCTP().AddNewR().AddNewCommentReference().id = comment1.Id;

    var paragraph2 = doc.CreateParagraph();
    paragraph2.CreateRun().SetText("This is ");
    paragraph2.GetCTP().AddNewCommentRangeStart().id = comment2.Id;
    paragraph2.CreateRun().SetText("2nd comment");
    paragraph2.GetCTP().AddNewCommentRangeEnd().id = comment2.Id;
    paragraph2.CreateRun().SetText(" text.");
    paragraph2.GetCTP().AddNewR().AddNewCommentReference().id = comment2.Id;

    using (FileStream sw = File.Create("comments.docx"))
    {
        doc.Write(sw);
    }
}