Fix Flashing Hover Popover (#8238)

Release Notes:

- Use an inclusive range for local range containment check to match LSP
behavior & fix popover flashing while the cursor moves over the last
character of a symbol.


https://github.com/zed-industries/zed/assets/17223924/6c3ddc9c-04fb-4414-812f-025ede5ecaf7

crates/editor/src/element.rs

@@ -894,6 +894,7 @@ impl EditorElement {
         cx: &mut ElementContext,
     ) {
         let start_row = layout.visible_display_row_range.start;
+        // Offset the content_bounds from the text_bounds by the gutter margin (which is roughly half a character wide) to make hit testing work more like how we want.
         let content_origin =
             text_bounds.origin + point(layout.gutter_dimensions.margin, Pixels::ZERO);
         let line_end_overshoot = 0.15 * layout.position_map.line_height;

crates/editor/src/hover_popover.rs

@@ -199,9 +199,10 @@ fn show_hover(
             if symbol_range
                 .as_text_range()
                 .map(|range| {
-                    range
-                        .to_offset(&snapshot.buffer_snapshot)
-                        .contains(&multibuffer_offset)
+                    let hover_range = range.to_offset(&snapshot.buffer_snapshot);
+                    // LSP returns a hover result for the end index of ranges that should be hovered, so we need to
+                    // use an inclusive range here to check if we should dismiss the popover
+                    (hover_range.start..=hover_range.end).contains(&multibuffer_offset)
                 })
                 .unwrap_or(false)
             {