[4/N] [libcxx] Reorder the two u8path functions, to make the following diff more readable. NFC.

[curdeius]

LGTM

[mstorsjo]

Rebased

[mstorsjo]

Rebased, readd the repository

[mstorsjo]

Rebased on top of D93283.

libcxx/include/filesystem

 
 inline _LIBCPP_INLINE_VISIBILITY void swap(path& __lhs, path& __rhs) noexcept {
   __lhs.swap(__rhs);
 }
 
 _LIBCPP_FUNC_VIS
 size_t hash_value(const path& __p) noexcept;
 
+template <class _InputIt>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_DEPRECATED_WITH_CHAR8_T
+    typename enable_if<__is_pathable<_InputIt>::value, path>::type
+    u8path(_InputIt __f, _InputIt __l) {
+  static_assert(
+#ifndef _LIBCPP_NO_HAS_CHAR8_T
+      // Proposed in P1423
+      is_same<typename __is_pathable<_InputIt>::__char_type, char8_t>::value ||
+#endif
+      is_same<typename __is_pathable<_InputIt>::__char_type, char>::value,
+      "u8path(Iter, Iter) requires Iter have a value_type of type 'char'");
+  return path(__f, __l);
+}
+
 template <class _Source>
 _LIBCPP_INLINE_VISIBILITY _LIBCPP_DEPRECATED_WITH_CHAR8_T
     typename enable_if<__is_pathable<_Source>::value, path>::type
     u8path(const _Source& __s) {
   static_assert(
 #ifndef _LIBCPP_NO_HAS_CHAR8_T
       // Proposed in P1423
       is_same<typename __is_pathable<_Source>::__char_type, char8_t>::value ||
 #endif
       is_same<typename __is_pathable<_Source>::__char_type, char>::value,
       "u8path(Source const&) requires Source have a character type of type "
       "'char'");
   return path(__s);
 }
 
-template <class _InputIt>
-_LIBCPP_INLINE_VISIBILITY _LIBCPP_DEPRECATED_WITH_CHAR8_T
-    typename enable_if<__is_pathable<_InputIt>::value, path>::type
-    u8path(_InputIt __f, _InputIt __l) {
-  static_assert(
-#ifndef _LIBCPP_NO_HAS_CHAR8_T
-      // Proposed in P1423
-      is_same<typename __is_pathable<_InputIt>::__char_type, char8_t>::value ||
-#endif
-      is_same<typename __is_pathable<_InputIt>::__char_type, char>::value,
-      "u8path(Iter, Iter) requires Iter have a value_type of type 'char'");
-  return path(__f, __l);
-}
-
 class _LIBCPP_TYPE_VIS path::iterator {
 public:
   enum _ParserState : unsigned char {
     _Singular,
     _BeforeBegin,
     _InRootName,
     _InRootDir,
     _InFilenames,