add text with practical DCDC specs

This is based on a measurement for one PCB, not connected to the
main PCB yet, in free air.

c3pb-heizung-dcdc/c3pb-heizung-dcdc.kicad_sch

@@ -2620,6 +2620,11 @@
     (effects (font (size 1.27 1.27)) (justify left bottom))
     (uuid 293e1cec-d18c-4aa9-b20f-7345bc8d3a5d)
   )
+  (text "Achievable in practice without overtemp shutdown:\n20V, 1.5A\n29V, 1.0A"
+    (at 99.06 54.61 0)
+    (effects (font (size 1.27 1.27)) (justify left bottom))
+    (uuid c701485a-027d-439c-8929-a5f0c5eab812)
+  )
 
   (label "SW" (at 121.92 77.47 0)
     (effects (font (size 1.27 1.27)) (justify left bottom))