update README.md to reflect nix shell changes

README.md

@@ -1,9 +1,9 @@
 # any-nix-shell
-`fish` and `zsh` support for the `nix run` and `nix-shell` environments of the Nix package manager.
+`fish` and `zsh` support for the `nix shell` and `nix-shell` environments of the Nix package manager.
 
 Features:
 
-  * When entering a `nix run` or `nix-shell` environment, the shell stays the same.
+  * When entering a `nix shell` or `nix-shell` environment, the shell stays the same.
   * Inside those environments, your prompt prints the loaded packages to the right.
   * Alternatively, print that information by executing: `nix-shell-info`
   * `nix-shell --command` or the like still execute inside `bash`, such that scripts don't break.
@@ -81,4 +81,4 @@ The `any-nix-shell` command (which is used for enabling the plugin in a specific
 
 | Flag | Description |
 | - | - |
-| `--info-right` | While in a `nix run` or `nix-shell` environment, display information about the loaded packages at the right. |
+| `--info-right` | While in a `nix shell` or `nix-shell` environment, display information about the loaded packages at the right. |