refactor: Add simple clang-tidy readability checks (#6556)

This change enables the following clang-tidy checks:
-  readability-avoid-nested-conditional-operator,
-  readability-avoid-return-with-void-value,
-  readability-braces-around-statements,
-  readability-const-return-type,
-  readability-container-contains,
-  readability-container-size-empty,
-  readability-else-after-return,
-  readability-make-member-function-const,
-  readability-redundant-casting,
-  readability-redundant-inline-specifier,
-  readability-redundant-member-init,
-  readability-redundant-string-init,
-  readability-reference-to-constructed-temporary,
-  readability-static-definition

src/libxrpl/protocol/STVector256.cpp

@@ -19,8 +19,10 @@ STVector256::STVector256(SerialIter& sit, SField const& name) : STBase(name)
     auto const slice = sit.getSlice(sit.getVLDataLength());
 
     if (slice.size() % uint256::size() != 0)
+    {
         Throw<std::runtime_error>(
             "Bad serialization for STVector256: " + std::to_string(slice.size()));
+    }
 
     auto const cnt = slice.size() / uint256::size();