container: improve documentation

This change removes inconsistencies collected over time in this package.

Signed-off-by: Ophestra <cat@gensokyo.uk>

container/initmkdir.go

@@ -10,7 +10,7 @@ import (
 
 func init() { gob.Register(new(MkdirOp)) }
 
-// Mkdir appends an [Op] that creates a directory in the container filesystem.
+// Mkdir is a helper for appending [MkdirOp] to [Ops].
 func (f *Ops) Mkdir(name *check.Absolute, perm os.FileMode) *Ops {
 	*f = append(*f, &MkdirOp{name, perm})
 	return f