fd-util: rename CLOSE_AND_REPLACE() -> close_and_replace()

We have free_and_replace() and friends, they are all named with lower
letters, even they are macros, not functions.
For consistency, let's rename CLOSE_AND_REPLACE() with lower letters.

This also mekes the macro used more places.

src/basic/fd-util.h

@@ -98,7 +98,7 @@ static inline int make_null_stdio(void) {
         })
 
 /* Like free_and_replace(), but for file descriptors */
-#define CLOSE_AND_REPLACE(a, b)                 \
+#define close_and_replace(a, b)                 \
         ({                                      \
                 int *_fdp_ = &(a);              \
                 safe_close(*_fdp_);             \