Adds a way to toggle font size without settings adjustments (#24857)

Closes https://github.com/zed-industries/zed/issues/23505

Now `zed::IncreaseBufferFontSize` (and all the same UI- and
Buffer-related settings) action is parameterized with `{ "persist": true
}` (default).
Using `"persist": false` brings back resizing behavior prior to
https://github.com/zed-industries/zed/pull/23265


Release Notes:

- Added a way to toggle font size without settings adjustments

crates/outline/src/outline.rs

@@ -349,7 +349,7 @@ pub fn render_item<T>(
         font_family: settings.buffer_font.family.clone(),
         font_features: settings.buffer_font.features.clone(),
         font_fallbacks: settings.buffer_font.fallbacks.clone(),
-        font_size: settings.buffer_font_size().into(),
+        font_size: settings.buffer_font_size(cx).into(),
         font_weight: settings.buffer_font.weight,
         line_height: relative(1.),
         ..Default::default()