Update docs/guide/vpx.md

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
Signed-off-by: Connor Shea <connor.james.shea@gmail.com>

Author: connorshea

docs/guide/vpx.md

@@ -8,7 +8,7 @@ Use `vpx`, `vp exec`, and `vp dlx` to run binaries without switching between loc
 
 Use the other binary commands when you need stricter control:
 
-- `vpx` resolves a package binary locally first and will download it if not found
+- `vpx` resolves a package binary locally first by default and downloads it if not found; with `pkg@version`, `--package/-p`, or `--shell-mode`, it runs via `vp dlx`
 - `vp exec` runs a binary from the current project's `node_modules/.bin`
 - `vp dlx` runs a package binary without adding it as a dependency