Revise and clean up some icons (#35582)

This is really just a small beginning, as there are many other icons to
be revised and cleaned up. Our current set is a bit of a mess in terms
of dimension, spacing, stroke width, and terminology. I'm sure there are
more non-used icons I'm not covering here, too. We'll hopefully tackle
it all soon leading up to 1.0.

Closes https://github.com/zed-industries/zed/issues/35576

Release Notes:

- N/A

crates/zed/src/zed/quick_action_bar.rs

@@ -192,7 +192,7 @@ impl Render for QuickActionBar {
             };
             v_flex()
                 .child(
-                    IconButton::new("toggle_code_actions_icon", IconName::Bolt)
+                    IconButton::new("toggle_code_actions_icon", IconName::BoltOutlined)
                         .icon_size(IconSize::Small)
                         .style(ButtonStyle::Subtle)
                         .disabled(!has_available_code_actions)