The `nyc report --reporter html` command may fail to generate an HTML report because it attempts to create a file containing characters that are not allowed in filenames on Windows.

[yusuke-noda]

On Windows, if the sources property of a source map file contains characters that are invalid for Windows filenames (such as ? < > \ : * | ", like in "angular:script"), the nyc report --reporter html command fails to generate the HTML report because it attempts to create files containing these invalid characters.

[morgan-coded]

On Windows, invalid filename characters in generated HTML report paths look like the failure point.

I'd be happy to add a regression around that output path and map those characters before the file write.