Handle @docRoot in links

I generated docs for androidx and confirmed there were no instances of @docRoot remaining, except in one which does not use it in an <a> tag: https://cs.android.com/androidx/platform/frameworks/support/+/androidx-main:compose/ui/ui-graphics/src/commonMain/kotlin/androidx/compose/ui/graphics/colorspace/Rgb.kt;l=54

Test: Added a unit test, full androidx docs test described above.
Bug: 247258332
Change-Id: I542f6409e052f3c2a5301bc56b6c5c5bfdbc3b4f
2 files changed