Add --shell to fnm env commands in the README (#1222)

README.md

@@ -149,31 +149,31 @@ Check out the following guides for the shell you use:
 Add the following to your `.bashrc` profile:
 
 ```bash
-eval "$(fnm env --use-on-cd)"
+eval "$(fnm env --use-on-cd --shell bash)"
 ```
 
 #### Zsh
 
 Add the following to your `.zshrc` profile:
 
 ```zsh
-eval "$(fnm env --use-on-cd)"
+eval "$(fnm env --use-on-cd --shell zsh)"
 ```
 
 #### Fish shell
 
 Create `~/.config/fish/conf.d/fnm.fish` and add this line to it:
 
 ```fish
-fnm env --use-on-cd | source
+fnm env --use-on-cd --shell fish | source
 ```
 
 #### PowerShell
 
 Add the following to the end of your profile file:
 
 ```powershell
-fnm env --use-on-cd | Out-String | Invoke-Expression
+fnm env --use-on-cd --shell power-shell | Out-String | Invoke-Expression
 ```
 
 - For macOS/Linux, the profile is located at `~/.config/powershell/Microsoft.PowerShell_profile.ps1`