perf: Add more moves and optimize (#3845)

* Make slice constructor consistent

* Add more missing std::move for ref steals

* Add missing perfect forwarding for arg_v ctor

* Add missing move in arg_v constructor

* Revert "Add missing move in arg_v constructor"

This reverts commit 126fc7c524ea7a51b54720defd75de3470d69557.

* Add another missing move in cast.h

* Optimize object move ctor

* Don't do useless move

* Make move ctor same as nb

* Make obj move ctor same as nb

* Revert changes which break MSVC

include/pybind11/numpy.h

diff --git a/include/pybind11/numpy.h b/include/pybind11/numpy.h
index 7624c9f..d45fe42 100644
--- a/include/pybind11/numpy.h
+++ b/include/pybind11/numpy.h
@@ -640,9 +640,9 @@
 
         list names, formats, offsets;
         for (auto &descr : field_descriptors) {
-            names.append(descr.name);
-            formats.append(descr.format);
-            offsets.append(descr.offset);
+            names.append(std::move(descr.name));
+            formats.append(std::move(descr.format));
+            offsets.append(std::move(descr.offset));
         }
         return dtype(std::move(names), std::move(formats), std::move(offsets), itemsize);
     }