treewide: Switch to std::format

Reduce our dependence on fmtlib.

Change-Id: I1cc9b372aa366ae26d846470c8ab9d1d52e8db70
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/src/fd/ops.cpp b/src/fd/ops.cpp
index e8f3636..b0f2bef 100644
--- a/src/fd/ops.cpp
+++ b/src/fd/ops.cpp
@@ -1,8 +1,7 @@
-#include <fmt/format.h>
-
 #include <stdplus/exception.hpp>
 #include <stdplus/fd/ops.hpp>
 
+#include <format>
 #include <utility>
 
 namespace stdplus
@@ -22,7 +21,7 @@
         if (ret.size() == 0)
         {
             throw exception::WouldBlock(
-                fmt::format("{} missing {}B", name, data.size()));
+                std::format("{} missing {}B", name, data.size()));
         }
         data = data.subspan(ret.size());
     }
@@ -61,7 +60,7 @@
         if (ret.size() != 0 && r.size() == 0)
         {
             throw exception::WouldBlock(
-                fmt::format("{} is {}B/{}B", name, ret.size() % align, align));
+                std::format("{} is {}B/{}B", name, ret.size() % align, align));
         }
         ret = data.subspan(0, ret.size() + r.size());
     } while (ret.size() % align != 0);