When two documents have the same `outputPath`, only differing by
letter casing, there can be problems on case-insensitive file-systems:
Only one of each of the docs would end up being written.
Moreover, the Webpack 5 bundler will error if it comes across files
that have this kind of ambiguous paths.
This commit adds a new docType: `disambiguator`, which will display
a list of the docs that match an ambiguous path. Each of the ambiguous
docs is then given a unique path and outputPath to ensure there are no
collisions.
PR Close#41788
Pete Bacon Darwin