Allow for venv activation script to use pyenv (#33119)

Release Notes:

- Allows for configuration and use of `pyenv` as a virtual environment provider

crates/terminal/src/terminal_settings.rs

@@ -95,12 +95,14 @@ pub enum VenvSettings {
         /// to the current working directory. We recommend overriding this
         /// in your project's settings, rather than globally.
         activate_script: Option<ActivateScript>,
+        venv_name: Option<String>,
         directories: Option<Vec<PathBuf>>,
     },
 }
 
 pub struct VenvSettingsContent<'a> {
     pub activate_script: ActivateScript,
+    pub venv_name: &'a str,
     pub directories: &'a [PathBuf],
 }
 
@@ -110,9 +112,11 @@ impl VenvSettings {
             VenvSettings::Off => None,
             VenvSettings::On {
                 activate_script,
+                venv_name,
                 directories,
             } => Some(VenvSettingsContent {
                 activate_script: activate_script.unwrap_or(ActivateScript::Default),
+                venv_name: venv_name.as_deref().unwrap_or(""),
                 directories: directories.as_deref().unwrap_or(&[]),
             }),
         }
@@ -128,6 +132,7 @@ pub enum ActivateScript {
     Fish,
     Nushell,
     PowerShell,
+    Pyenv,
 }
 
 #[derive(Clone, Debug, Default, Serialize, Deserialize, JsonSchema)]