Document that in C++ PinholeProjection::from_mat3x3 is column major (#…

…4843)

### What

Another incorrect docstring.

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rerun_cpp/src/rerun/components/pinhole_projection_ext.cpp

@@ -12,7 +12,7 @@ namespace rerun {
 
             // <CODEGEN_COPY_TO_HEADER>
 
-            /// Construct a new 3x3 pinhole matrix from a pointer to 9 floats (in row major order).
+            /// Construct a new 3x3 pinhole matrix from a pointer to 9 floats (in column major order).
             static PinholeProjection from_mat3x3(const float* elements) {
                 return PinholeProjection(rerun::datatypes::Mat3x3(elements));
             }