doc/tutorial: address cuelang/cuelang.org#126

@j-bai raised cuelang/cuelang.org#126, pointing out that the roles of `xaxis` and `yaxis` are backwards. This addresses the issue.

Closes #711
cuelang/cue#711

GitOrigin-RevId: 186399f9040cd6111214f92cd8d1d94c5908ffd7
Change-Id: I439cf405ce4174d75917c550c9ef3b91ff9ab54c
Reviewed-on: https://cue-review.googlesource.com/c/cue/+/8622
Reviewed-by: CUE cueckoo <cueckoo@gmail.com>
Reviewed-by: Marcel van Lohuizen <mpvl@golang.org>

doc/tutorial/basics/2_types/05_types.txt

@@ -43,10 +43,10 @@ point: {
 }
 
 xaxis: point
-xaxis: x: 0
+xaxis: y: 0
 
 yaxis: point
-yaxis: y: 0
+yaxis: x: 0
 
 origin: xaxis & yaxis
 
@@ -56,13 +56,13 @@ point: {
     y: number
 }
 xaxis: {
-    x: 0
-    y: number
-}
-yaxis: {
     x: number
     y: 0
 }
+yaxis: {
+    x: 0
+    y: number
+}
 origin: {
     x: 0
     y: 0