[Bug] .NET API bug Property Value content not render correctly in generated Markdown

[cary-hu]

I have a Class with comment like this:

namespace ClassLibrary1
{
    /// <summary>
    /// This is a test class
    /// </summary>
    /// <seealso cref="System.Object"/>
    public class Class1
    {
        /// <summary>
        /// This is a test summary
        /// </summary>
        /// <value>
        /// <see langword="string"/> is test
        /// </value>
        public string TestStringProperty { get; set; }

    }
}

After build, I will got two files ClassLibrary1.dll and ClassLibrary1.xml, xml will with this content:

<?xml version="1.0"?>
<doc>
    <assembly>
        <name>ClassLibrary1</name>
    </assembly>
    <members>
        <member name="T:ClassLibrary1.Class1">
            <summary>
            This is a test class
            </summary>
            <seealso cref="T:System.Object"/>
        </member>
        <member name="P:ClassLibrary1.Class1.TestStringProperty">
            <summary>
            This is a test summary
            </summary>
            <value>
            <see langword="string"/> is test
            </value>
        </member>
    </members>
</doc>

Expected behavior

all the content should be rendered in generated markdown page.

but, the property value is not rendered correctly:

Context (please complete the following information):

• OS: Windows

• Docfx version: 2.78.2

• .NET version: .NET 8.0

• docfx.json config

{
    "metadata": [
        {
            "src": [
                {
                    "files": [
                        "*.dll"
                    ]
                }
            ],
            "dest": "./api",
            "outputFormat": "markdown"
        }
    ]
}

[filzrev]

I also confirmed reported issue can be reproduced.

It seems occurred when using apiPage or markdown output format.

It occurred because following lines don't set description property for Parameter type.
And it seems be resolved by adding description = comment.Returns, line.
https://github.com/dotnet/docfx/blob/main/src/Docfx.Dotnet/DotnetApiCatalog.ApiPage.cs#L559-L566