[dtype] change type() name method to char_() to be compliant with Python numpy interface

Author: Bertrand MICHEL

include/pybind11/numpy.h

@@ -513,7 +513,7 @@ class dtype : public object {
     }
 
     /// Single-character for dtype's type (ex: float is 'f' and double 'd')
-    char type() const {
+    char char_() const {
         return detail::array_descriptor_proxy(m_ptr)->type;
     }
 

tests/test_numpy_dtypes.cpp

@@ -278,7 +278,7 @@ py::list test_dtype_type() {
                      py::dtype("float64"), // double
                      py::dtype("float128") // long double
                     }) {
-        list.append(dt.type());
+        list.append(dt.char_());
     }
     return list;
 }