## Changes
While working on #1273, I found that calls to `Append` on a
`dyn.Pattern` were mutating the original slice. This is expected because
appending to a slice will mutate in place if the capacity of the
original slice is large enough. This change updates the `Append` call on
the `dyn.Path` as well to return a newly allocated slice to avoid
inadvertently mutating the originals.
We have existing call sites in the `dyn` package that mutate a
`dyn.Path` (e.g. walk or visit) and these are modified to continue to do
this with a direct call to `append`. Callbacks that use the `dyn.Path`
argument outside of the callback need to make a copy to ensure it isn't
mutated (this is no different from existing semantics).
The `Join` function wasn't used and is removed as part of this change.
## Tests
Unit tests.
## Changes
The name "dynamic value", or "dyn" for short, is more descriptive than
the opaque "config". Also, it conveniently does not alias with other
packages in the repository, or (popular ones) elsewhere.
(discussed with @andrewnester)
## Tests
n/a
Pieter Noordhuis