examples: Remove unused doc comments. (bevyengine#9795)

# Objective

- Compile all targets without warnings about unused doc comments.

## Solution

- Turn unused doc comments into regular comments. Doc comments aren't
supported on expressions, so they can just be regular comments.

examples/ui/grid.rs

@@ -23,19 +23,19 @@ fn spawn_layout(mut commands: Commands, asset_server: Res<AssetServer>) {
  commands
  .spawn(NodeBundle {
  style: Style {
- /// Use the CSS Grid algorithm for laying out this node
+ // Use the CSS Grid algorithm for laying out this node
  display: Display::Grid,
- /// Make node fill the entirety it's parent (in this case the window)
+ // Make node fill the entirety it's parent (in this case the window)
  width: Val::Percent(100.0),
  height: Val::Percent(100.0),
- /// Set the grid to have 2 columns with sizes [min-content, minmax(0, 1fr)]
- /// - The first column will size to the size of it's contents
- /// - The second column will take up the remaining available space
+ // Set the grid to have 2 columns with sizes [min-content, minmax(0, 1fr)]
+ // - The first column will size to the size of it's contents
+ // - The second column will take up the remaining available space
  grid_template_columns: vec![GridTrack::min_content(), GridTrack::flex(1.0)],
- /// Set the grid to have 3 rows with sizes [auto, minmax(0, 1fr), 20px]
- /// - The first row will size to the size of it's contents
- /// - The second row take up remaining available space (after rows 1 and 3 have both been sized)
- /// - The third row will be exactly 20px high
+ // Set the grid to have 3 rows with sizes [auto, minmax(0, 1fr), 20px]
+ // - The first row will size to the size of it's contents
+ // - The second row take up remaining available space (after rows 1 and 3 have both been sized)
+ // - The third row will be exactly 20px high
  grid_template_rows: vec![
  GridTrack::auto(),
  GridTrack::flex(1.0),
@@ -52,7 +52,7 @@ fn spawn_layout(mut commands: Commands, asset_server: Res<AssetServer>) {
  .spawn(NodeBundle {
  style: Style {
  display: Display::Grid,
- /// Make this node span two grid columns so that it takes up the entire top tow
+ // Make this node span two grid columns so that it takes up the entire top tow
  grid_column: GridPlacement::span(2),
  padding: UiRect::all(Val::Px(6.0)),
  ..default()
@@ -67,22 +67,22 @@ fn spawn_layout(mut commands: Commands, asset_server: Res<AssetServer>) {
  builder
  .spawn(NodeBundle {
  style: Style {
- /// Make the height of the node fill its parent
+ // Make the height of the node fill its parent
  height: Val::Percent(100.0),
- /// Make the grid have a 1:1 aspect ratio meaning it will scale as an exact square
- /// As the height is set explicitly, this means the width will adjust to match the height
+ // Make the grid have a 1:1 aspect ratio meaning it will scale as an exact square
+ // As the height is set explicitly, this means the width will adjust to match the height
  aspect_ratio: Some(1.0),
- /// Use grid layout for this node
+ // Use grid layout for this node
  display: Display::Grid,
  // Add 24px of padding around the grid
  padding: UiRect::all(Val::Px(24.0)),
- /// Set the grid to have 4 columns all with sizes minmax(0, 1fr)
- /// This creates 4 exactly evenly sized columns
+ // Set the grid to have 4 columns all with sizes minmax(0, 1fr)
+ // This creates 4 exactly evenly sized columns
  grid_template_columns: RepeatedGridTrack::flex(4, 1.0),
- /// Set the grid to have 4 rows all with sizes minmax(0, 1fr)
- /// This creates 4 exactly evenly sized rows
+ // Set the grid to have 4 rows all with sizes minmax(0, 1fr)
+ // This creates 4 exactly evenly sized rows
  grid_template_rows: RepeatedGridTrack::flex(4, 1.0),
- /// Set a 12px gap/gutter between rows and columns
+ // Set a 12px gap/gutter between rows and columns
  row_gap: Val::Px(12.0),
  column_gap: Val::Px(12.0),
  ..default()