LOAD blocks cannot create a ROM section

Fixes #576

src/asm/section.c

@@ -339,6 +339,9 @@ void out_SetLoadSection(char const *name, uint32_t type, uint32_t org,
 	if (currentLoadSection)
 		fatalerror("`LOAD` blocks cannot be nested\n");
 
+	if (sect_HasData(type))
+		error("`LOAD` blocks cannot create a ROM section\n");
+
 	struct Section *sect = getSection(name, type, org, attribs, false);
 
 	loadOffset = curOffset;

test/asm/load-rom.asm

@@ -0,0 +1,5 @@
+SECTION "Hello", ROM0
+	ld a, 1
+LOAD "Wello", ROM0
+	ld a, 2
+ENDL

test/asm/load-rom.err

@@ -0,0 +1,3 @@
+ERROR: load-rom.asm(3):
+    `LOAD` blocks cannot create a ROM section
+error: Assembly aborted (1 errors)!