docs: replace h3 with h2 headings (#1452)

docs/src/pages/components/Popover.svx

@@ -3,7 +3,7 @@
   import Preview from "../../components/Preview.svelte";
 </script>
 
-### Default
+## Default
 
 By default, the position of the popover component is absolute.
 
@@ -14,7 +14,7 @@ By default, the position of the popover component is absolute.
     </Popover>
 </div>
 
-### Relative position
+## Relative position
 
 Set `relative` to `true` to use a relative position.
 
@@ -25,7 +25,7 @@ Set `relative` to `true` to use a relative position.
     </Popover>
 </div>
 
-### Close on outside click
+## Close on outside click
 
 Set `closeOnOutsideClick` to set `open` to `false` when clicking outside of the popover.
 
@@ -36,7 +36,7 @@ Set `closeOnOutsideClick` to set `open` to `false` when clicking outside of the
     </Popover>
 </div>
 
-### Popover alignment
+## Popover alignment
 
 Customize the popover alignment using the `align` prop. Valid values include: `"top" | "top-left" | "top-right" | "bottom" | "bottom-left" | "bottom-right" | "left" | "left-bottom" | "left-top" | "right" | "right-bottom" | "right-top"`.
 
@@ -109,7 +109,7 @@ The default `align` value is `"top"`.
     </Popover>
 </div>
 
-### With caret
+## With caret
 
 <div data-outline>
     Parent
@@ -118,7 +118,7 @@ The default `align` value is `"top"`.
     </Popover>
 </div>
 
-### Custom caret alignment
+## Custom caret alignment
 
 By default, the caret is aligned "top".
 
@@ -131,7 +131,7 @@ Possible `align` values include `"top"`, `"top-left"`, `"top-right"`, `"bottom"`
     </Popover>
 </div>
 
-### Light variant
+## Light variant
 
 <div data-outline>
     Parent
@@ -140,7 +140,7 @@ Possible `align` values include `"top"`, `"top-left"`, `"top-right"`, `"bottom"`
     </Popover>
 </div>
 
-### High contrast variant
+## High contrast variant
 
 <div data-outline>
     Parent