Add changelog entry

changelog/std-format-formattedWrite.dd

@@ -0,0 +1,19 @@
+`std.format.formattedWrite` now accepts a compile-time checked format string
+
+$(REF formattedWrite, std, format) and related functions now have overloads to
+take the format string as a compile-time argument. This allows the format
+specifiers to be matched against the argument types passed. Any mismatch or
+orphaned specifiers/arguments will cause a compile-time error:
+
+-------
+import std.format;
+
+void main() {
+    auto s = format!"%s is %s"("Pi", 3.14);
+    assert(s == "Pi is 3.14");
+
+    static assert(!__traits(compiles, {s = format!"%l"();}));     // missing arg
+    static assert(!__traits(compiles, {s = format!""(404);}));    // surplus arg
+    static assert(!__traits(compiles, {s = format!"%d"(4.03);})); // incompatible arg
+}
+-------