refactor: Fix spelling issues in tests (#6199)

This change removes the `src/tests` exception from the `cspell` config and fixes all the issues that arise as a result. No functionality/test change.

src/test/rpc/Transaction_test.cpp

@@ -512,7 +512,7 @@ class Transaction_test : public beast::unit_test::suite
     }
 
     void
-    testCTIDRPC(FeatureBitset features)
+    testRPCsForCTID(FeatureBitset features)
     {
         testcase("CTID RPC");
 
@@ -804,7 +804,7 @@ public:
         testRangeRequest(features);
         testRangeCTIDRequest(features);
         testCTIDValidation(features);
-        testCTIDRPC(features);
+        testRPCsForCTID(features);
         forAllApiVersions(std::bind_front(&Transaction_test::testRequest, this, features));
     }
 };