Remove the last uses of _format()

Three of the four cases are simple, we can use fmt::format and don't
need to parse a format string. The last case has the format string
R"(\u{:04x})" to parse, but that's only needed when some control
characters are written out in JSON format, which doesn't happen that
often.

Fixes #1704

Author: joto

src/format.hpp

@@ -15,9 +15,6 @@
 
 #include <stdexcept>
 
-// NOLINTNEXTLINE(google-global-names-in-headers,google-build-using-namespace)
-using namespace fmt::literals;
-
 template <typename S, typename... TArgs>
 std::runtime_error fmt_error(S const &format_str, TArgs &&...args)
 {

src/json-writer.hpp

@@ -30,7 +30,7 @@ class json_writer_t
     void number(T value)
     {
         if (std::isfinite(value)) {
-            fmt::format_to(std::back_inserter(m_buffer), "{}"_format(value));
+            m_buffer += fmt::to_string(value);
         } else {
             null();
         }
@@ -39,7 +39,7 @@ class json_writer_t
     template <typename T, std::enable_if_t<std::is_integral_v<T>, bool> = true>
     void number(T value)
     {
-        fmt::format_to(std::back_inserter(m_buffer), "{}"_format(value));
+        m_buffer += fmt::to_string(value);
     }
 
     void string(char const *str)
@@ -70,8 +70,8 @@ class json_writer_t
                 break;
             default:
                 if (c <= 0x1f) {
-                    m_buffer.append(
-                        R"(\u{:04x})"_format(static_cast<unsigned char>(c)));
+                    m_buffer.append(fmt::format(R"(\u{:04x})",
+                                                static_cast<unsigned char>(c)));
                 } else {
                     m_buffer += c;
                 }

src/pgsql.hpp

@@ -138,7 +138,8 @@ struct exec_arg
     constexpr static std::size_t const buffers_needed = 1;
     static char const *to_str(std::vector<std::string> *data, T param)
     {
-        return data->emplace_back("{}"_format(std::forward<T>(param))).c_str();
+        return data->emplace_back(fmt::to_string(std::forward<T>(param)))
+            .c_str();
     }
 };