20e9899835
Findings 1-3 from self-review (4dce8e4):
Finding 1 [NIT]: remove dead ModeSymlink check and its misleading
'defense-in-depth' comment. After filepath.EvalSymlinks, resolvedPath
is guaranteed symlink-free; fi.Mode()&os.ModeSymlink can never be set.
Dropped the unreachable branch; updated Lstat comment to say so.
Finding 2 [MINOR]: update validateDocmapPath godoc — invariant #2 now
reads 'The resolved path is within resolvedRoot' instead of 'The path
is not a symlink'. In-repo file-level symlinks whose resolved target
stays within the root are allowed; the confinement check enforces the
actual invariant.
Finding 3 [MINOR]: update inline comment in runValidateDocmap — the
bulleted list item now says 'Resolved target stays within the root
(in-repo symlinks allowed...)' instead of 'Is not a symlink'.