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/ledger/CachedView.cpp

@@ -40,11 +40,17 @@ CachedViewImpl::read(Keylet const& k) const
     // If the sle is null, then a failure must have occurred in base_.read()
     XRPL_ASSERT(sle || baseRead, "xrpl::CachedView::read : null SLE result from base");
     if (cacheHit && baseRead)
+    {
         hitsexpired.increment();
+    }
     else if (cacheHit)
+    {
         hits.increment();
+    }
     else
+    {
         misses.increment();
+    }
 
     if (!cacheHit)
     {