template/unit: add table of contents
Remove unnecessary shadowed variables
Add declaration list to index
Convert to original filenames earlier
Add index
Rename docData to unitData
Fix duplicate symbols
Only load templates once
Highlight headings when targeted by anchor
Rename index.html to unit.html

This represents a single translation unit.
readme: strip /usr/include/ from output filepaths
Default outputDir to "out"
Add -ffile-prefix-map
Write docs to a directory
Evaluate symlinks
Accept directory as input file
Move docData variable down
Add -o to set output file
Add anchor links for headings
Don't panic on -fexported-symbols without value