[v11.0.x] Docs: fix duplicate headings (#85973)

Docs: fix duplicate headings (#85903)

Added suffix to one Placement heading

(cherry picked from commit 2798acd667)

Co-authored-by: Isabel Matwawana <76437239+imatwawana@users.noreply.github.com>

docs/sources/panels-visualizations/visualizations/xy-chart/index.md

@@ -146,7 +146,7 @@ Legend options control the series names and statistics that appear under or to t
 
 Options under the axis category change how the x- and y-axes are rendered. Some options don't take effect until you click outside of the field option box you are editing. You can also or press `Enter`.
 
-### Placement
+### Placement (y-axis)
 
 Select the placement of the y-axis.