Minor documentation changes

doc/api.rst

@@ -58,29 +58,26 @@ formatting::
 The format string syntax is described in the documentation of
 `strftime <http://en.cppreference.com/w/cpp/chrono/c/strftime>`_.
 
-Formatting User-Defined types
+Formatting user-defined types
 -----------------------------
 
-A custom ``format_arg`` function may be implemented and used to format any user-
-defined type. That is how date and time formatting described in the previous
-section is implemented in :file:`fmt/time.h`. The following example shows how to implement custom formatting for a user-defined structure. 
+A custom ``format_arg`` function may be implemented and used to format any
+user-defined type. That is how date and time formatting described in the
+previous section is implemented in :file:`fmt/time.h`. The following example
+shows how to implement custom formatting for a user-defined structure.
 
 ::
 
-  struct MyStruct { double a, b, c, d; };
+  struct MyStruct { double a, b; };
 
   void format_arg(fmt::BasicFormatter<char> &f,
-      const char *&format_str, const MyStruct &s) {
-      f.writer().write("[MyStruct: a={:.1f}, b={:.2f}, c={:.3f}, d={:.4f}]",
-          s.a, s.b, s.c, s.d);
+    const char *&format_str, const MyStruct &s) {
+    f.writer().write("[MyStruct: a={:.1f}, b={:.2f}]", s.a, s.b);
   }
 
-  void f()
-  {
-      MyStruct m = { 1, 2, 3, 4 };
-      std::string s = fmt::format("m={}", n);
-      // s == "m=[MyStruct: a=1.0, b=2.00, c=3.000, d=4.0000]"
-  }
+  MyStruct m = { 1, 2 };
+  std::string s = fmt::format("m={}", n);
+  // s == "m=[MyStruct: a=1.0, b=2.00]"
 
 Note in the example above the ``format_arg`` function ignores the contents of
 ``format_str`` so the type will always be formatted as specified. See