moved constants out of the namespace as msvc complains about it

Author: staxfur

cpp-terminal/private/conversion.hpp

@@ -13,10 +13,11 @@
 
 #endif
 
-namespace Term::Private {
 static constexpr uint8_t UTF8_ACCEPT = 0;
 static constexpr uint8_t UTF8_REJECT = 0xf;
 
+namespace Term::Private {
+
 inline uint8_t utf8_decode_step(uint8_t state, uint8_t octet, uint32_t* cpp) {
  static const uint32_t utf8_classtab[0x10] = {
  0x88888888UL, 0x88888888UL, 0x99999999UL, 0x99999999UL,