Lists should be rendered with <item>

[carlossanlop]

As suggested here: dotnet/runtime#46716 (comment)

Lists should be rendered with <item>

Example: https://github.com/dotnet/roslyn/blob/b09625add4da1b872e8033d2775ea514786d86e1/src/Features/Core/Portable/DocumentationComments/AbstractDocumentationCommentFormattingService.cs#L43-L56

[danmoseley]

also reject attempts at HTML. Eg., this

        ///   <list type="bullet">
        ///     <item><description>set the <see cref="IHostEnvironment.ContentRootPath"/> to the result of <see cref="Directory.GetCurrentDirectory()"/></description></item>

produces build warnings like

Line 0, Column 0: [Suggestion-disallowed-html-tag] HTML tag 'list' isn't allowed. Disallowed HTML poses a security risk and must be replaced with approved Docs Markdown syntax.
Line 0, Column 0: [Suggestion-disallowed-html-tag] HTML tag 'item' isn't allowed. Disallowed HTML poses a security risk and must be replaced with approved Docs Markdown syntax.
Line 0, Column 0: [Suggestion-disallowed-html-tag] HTML tag 'description' isn't allowed. Disallowed HTML poses a security risk and must be replaced with approved Docs Markdown syntax.

The tool should at least grep for these and fail out.