Refactor how map file sections are printed

This makes size-0 sections print as "($0000 bytes)" instead of
"(0 bytes)", which is more consistent.

test/link/map-file/a.asm

@@ -25,3 +25,5 @@ wLabel1:: ds 6
 SECTION "hram", HRAM
 hLabel:: ds 7
 .local::
+
+SECTION "\n\r\t\"\\", ROM0[1]

test/link/map-file/ref.out.map

@@ -10,6 +10,7 @@ ROM0 bank #0:
 	SECTION: $0000-$0000 ($0001 byte) ["rom0"]
 	         $0000 = Label0
 	         $0001 = Label0.local
+	SECTION: $0001 ($0000 bytes) ["\n\r\t\"\\"]
 	EMPTY: $0001-$3fff ($3fff bytes)
 	TOTAL EMPTY: $3fff bytes