Remove printing facilities for Regular_Expression

The `original_pattern` introduced a tenuous dependency to the expression
value as a whole, and after some consideration, I decided that it would
be better for the developer to manage their own pattern strings.

In the event you need to print the text representation of a pattern,
it's usually better that you manage the memory of it as well.

core/text/regex/regex.odin

@@ -30,7 +30,6 @@ Capture :: struct {
 }
 
 Regular_Expression :: struct {
-	original_pattern: string,
 	flags: Flags,
 	class_data: []virtual_machine.Rune_Class_Data,
 	program: []virtual_machine.Opcode `fmt:"-"`,
@@ -92,7 +91,6 @@ create :: proc(
 	// allocator so everything can be tightly packed.
 	context.allocator = permanent_allocator
 
-	result.original_pattern = pattern
 	result.flags = flags
 
 	if len(class_data) > 0 {