sha1_name.c: rename to use dash in file name

This is more consistent with the project style. The majority of Git's
source files use dashes in preference to underscores in their file names.

Signed-off-by: Stefan Beller <sbeller@google.com>

Makefile

@@ -901,7 +901,7 @@ LIB_OBJS += setup.o
 LIB_OBJS += sha1-array.o
 LIB_OBJS += sha1-lookup.o
 LIB_OBJS += sha1_file.o
-LIB_OBJS += sha1_name.o
+LIB_OBJS += sha1-name.o
 LIB_OBJS += shallow.o
 LIB_OBJS += sideband.o
 LIB_OBJS += sigchain.o

list-objects-filter.c

@@ -19,7 +19,7 @@
  * in the traversal (until we mark it SEEN).  This is a way to
  * let us silently de-dup calls to show() in the caller.  This
  * is subtly different from the "revision.h:SHOWN" and the
- * "sha1_name.c:ONELINE_SEEN" bits.  And also different from
+ * "sha1-name.c:ONELINE_SEEN" bits.  And also different from
  * the non-de-dup usage in pack-bitmap.c
  */
 #define FILTER_SHOWN_BUT_REVISIT (1<<21)

object.h

@@ -37,7 +37,7 @@ struct object_array {
  * bundle.c:                                        16
  * http-push.c:                                     16-----19
  * commit.c:                                        16-----19
- * sha1_name.c:                                              20
+ * sha1-name.c:                                              20
  * list-objects-filter.c:                                      21
  * builtin/fsck.c:           0--3
  * builtin/index-pack.c:                                     2021