Appropriately pick venv activation script (#33205)

when `terminal.detect_venv.activate_script` setting is default, pick the
appropriate activate script as per the `terminal.shell` settings
specified by the user. Previously when the activate_script setting is
default, zed always try to use the `activate` script, which only works
when the user shell is `bash or zsh`. But what if the user is using
`fish` shell in zed?

Release Notes:

- python: value of `activate_script` setting is now automatically
inferred based on the kind of shell the user is running with.

---------

Co-authored-by: Piotr Osiewicz <24362066+osiewicz@users.noreply.github.com>

crates/terminal/src/terminal_settings.rs

@@ -123,7 +123,7 @@ impl VenvSettings {
     }
 }
 
-#[derive(Clone, Copy, Debug, Default, Serialize, Deserialize, JsonSchema)]
+#[derive(Clone, Copy, Debug, Default, PartialEq, Serialize, Deserialize, JsonSchema)]
 #[serde(rename_all = "snake_case")]
 pub enum ActivateScript {
     #[default]