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/test/jtx/impl/AMMTest.cpp

@@ -129,11 +129,17 @@ AMMTestBase::testAMM(std::function<void(jtx::AMM&, jtx::Env&)> const& cb, TestAM
         BEAST_EXPECT(asset1 <= toFund1 && asset2 <= toFund2);
 
         if (!asset1.native() && !asset2.native())
+        {
             fund(env, gw, {alice, carol}, {toFund1, toFund2}, Fund::All);
+        }
         else if (asset1.native())
+        {
             fund(env, gw, {alice, carol}, toFund1, {toFund2}, Fund::All);
+        }
         else if (asset2.native())
+        {
             fund(env, gw, {alice, carol}, toFund2, {toFund1}, Fund::All);
+        }
 
         AMM ammAlice(
             env, alice, asset1, asset2, CreateArg{.log = false, .tfee = arg.tfee, .err = arg.ter});