Add support for unicode chars in the 0x10000 - 0x10FFFF range as required by spec

source/dyaml/reader.d

@@ -926,7 +926,8 @@ bool isPrintableValidUTF8(const char[] chars) @trusted pure nothrow @nogc
         const dchar c = decodeValidUTF8NoGC(chars, index);
         // We now c is not ASCII, so only check for printable non-ASCII chars.
         if(!(c == 0x85 || (c >= 0xA0 && c <= '\uD7FF') ||
-            (c >= '\uE000' && c <= '\uFFFD')))
+            (c >= '\uE000' && c <= '\uFFFD') ||
+            (c >= '\U00010000' && c <= '\U0010FFFF')))
         {
             return false;
         }

test/data/bmpchars.canonical

@@ -0,0 +1,6 @@
+%YAML 1.1
+---
+!!map {
+  ? !!str "a"
+  : !!str "𒅗"
+}

test/data/bmpchars.data

@@ -0,0 +1 @@
+a: 𒅗