lib: remove optional builtins prefixes from prelude functions

Remove optional builtins prefixes from prelude functions by running:

    builtins=(
      abort
      baseNameOf
      break
      derivation
      derivationStrict
      dirOf
      false
      fetchGit
      fetchMercurial
      fetchTarball
      fetchTree
      fromTOML
      import
      isNull
      map
      null
      placeholder
      removeAttrs
      scopedImport
      throw
      toString
      true
    )

    fd --type file . lib --exec-batch sed --in-place --regexp-extended "
      s/\<builtins\.($(
        printf '%s\n' "${builtins[@]}" |
          paste --delimiter '|' --serial -
      ))\>/\1/g
    "

    nix fmt

lib/asserts.nix

@@ -47,7 +47,7 @@ rec {
     :::
   */
   # TODO(Profpatsch): add tests that check stderr
-  assertMsg = pred: msg: pred || builtins.throw msg;
+  assertMsg = pred: msg: pred || throw msg;
 
   /**
     Specialized `assertMsg` for checking if `val` is one of the elements