Hoist the SECTION comment in opncls.c

The opening and closing node in BFD starts:

    File: bfd.info, [...]

	 /* Set to N to open the next N BFDs using an alternate id space.  */
	 extern unsigned int bfd_use_reserved_id;

    2.13 Opening and closing BFDs
    =============================

That is, there's a stray C comment and declaration before any other
text or subsections.

This occurs because the code fragment for bfd_use_reserved_id comes
before the SECTION comment.  Hoisting it makes this a little nicer.

2023-02-17  Tom Tromey  <tom@tromey.com>

	* opncls.c: Hoist the SECTION comment.

bfd/ChangeLog

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index a974a5c..fac38b8 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,5 +1,9 @@
 2023-02-17  Tom Tromey  <tom@tromey.com>
 
+	* opncls.c: Hoist the SECTION comment.
+
+2023-02-17  Tom Tromey  <tom@tromey.com>
+
 	* opncls.c (bfd_get_debug_link_info_1, separate_debug_file_exists)
 	(separate_alt_debug_file_exists, find_separate_debug_file)
 	(get_build_id, get_build_id_name, check_build_id_file): Don't use

bfd/opncls.c

diff --git a/bfd/opncls.c b/bfd/opncls.c
index 3fa2b03..4d0ca48 100644
--- a/bfd/opncls.c
+++ b/bfd/opncls.c
@@ -37,6 +37,14 @@
 #define S_IXOTH 0001	/* Execute by others.  */
 #endif
 
+/*
+SECTION
+	Opening and closing BFDs
+
+SUBSECTION
+	Functions for opening and closing
+*/
+
 /* Counters used to initialize the bfd identifier.  */
 
 static unsigned int bfd_id_counter = 0;
@@ -186,14 +194,6 @@
 }
 
 /*
-SECTION
-	Opening and closing BFDs
-
-SUBSECTION
-	Functions for opening and closing
-*/
-
-/*
 FUNCTION
 	bfd_fopen