Replace core:* to base:* where appropriate

core/fmt/fmt.odin

@@ -4,12 +4,12 @@ import "core:math/bits"
 import "core:mem"
 import "core:io"
 import "core:reflect"
-import "core:runtime"
+import "base:runtime"
 import "core:strconv"
 import "core:strings"
 import "core:time"
 import "core:unicode/utf8"
-import "core:intrinsics"
+import "base:intrinsics"
 
 // Internal data structure that stores the required information for formatted printing
 Info :: struct {

core/fmt/fmt_os.odin

@@ -2,7 +2,7 @@
 //+build !js
 package fmt
 
-import "core:runtime"
+import "base:runtime"
 import "core:os"
 import "core:io"
 import "core:bufio"