Trim two stale lint suppressions in serializer.hpp

dump_integer()'s `auto buffer_ptr = number_buffer.begin();` carried
NOLINT entries for cppcoreguidelines-pro-type-vararg and hicpp-vararg,
left over from the snprintf-based implementation (#3088); there is no
variadic call on that line, so keep only the qualified-auto
suppressions it actually needs. remove_sign()'s assert checked
`x < 0 && x < (std::numeric_limits<number_integer_t>::max)()) `with a
NOLINT(misc-redundant-expression) to hide it; the second conjunct is
always true once x < 0, and has been since 6ce2f35ba (2019), so
reduce the assert to `x < 0` and drop the suppression instead of
masking it.

Both are documentation-only changes to assertions/suppressions, not
behavior. The to_chars.hpp `#if 0` branch this item also flagged is
left alone, next to draft PR #5634's pending hunk.

Part of #5709

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

include/nlohmann/detail/output/serializer.hpp

@@ -1345,7 +1345,7 @@ class serializer
         }
 
         // use a pointer to fill the buffer
-        auto buffer_ptr = number_buffer.begin(); // NOLINT(llvm-qualified-auto,readability-qualified-auto,cppcoreguidelines-pro-type-vararg,hicpp-vararg)
+        auto buffer_ptr = number_buffer.begin(); // NOLINT(llvm-qualified-auto,readability-qualified-auto)
 
         number_unsigned_t abs_value;
 
@@ -1519,7 +1519,7 @@ class serializer
      */
     number_unsigned_t remove_sign(number_integer_t x) noexcept
     {
-        JSON_ASSERT(x < 0 && x < (std::numeric_limits<number_integer_t>::max)()); // NOLINT(misc-redundant-expression)
+        JSON_ASSERT(x < 0);
         return static_cast<number_unsigned_t>(-(x + 1)) + 1;
     }
 

single_include/nlohmann/json.hpp

@@ -25426,7 +25426,7 @@ class serializer
         }
 
         // use a pointer to fill the buffer
-        auto buffer_ptr = number_buffer.begin(); // NOLINT(llvm-qualified-auto,readability-qualified-auto,cppcoreguidelines-pro-type-vararg,hicpp-vararg)
+        auto buffer_ptr = number_buffer.begin(); // NOLINT(llvm-qualified-auto,readability-qualified-auto)
 
         number_unsigned_t abs_value;
 
@@ -25600,7 +25600,7 @@ class serializer
      */
     number_unsigned_t remove_sign(number_integer_t x) noexcept
     {
-        JSON_ASSERT(x < 0 && x < (std::numeric_limits<number_integer_t>::max)()); // NOLINT(misc-redundant-expression)
+        JSON_ASSERT(x < 0);
         return static_cast<number_unsigned_t>(-(x + 1)) + 1;
     }