C++: Enable implicit this warnings

cpp/ql/lib/qlpack.yml

@@ -9,3 +9,4 @@ dependencies:
   codeql/ssa: ${workspace}
   codeql/tutorial: ${workspace}
   codeql/util: ${workspace}
+warnOnImplicitThis: true

cpp/ql/src/qlpack.yml

@@ -10,3 +10,4 @@ dependencies:
 suites: codeql-suites
 extractor: cpp
 defaultSuiteFile: codeql-suites/cpp-code-scanning.qls
+warnOnImplicitThis: true

cpp/ql/test/qlpack.yml

@@ -5,3 +5,4 @@ dependencies:
   codeql/cpp-queries: ${workspace}
 extractor: cpp
 tests: .
+warnOnImplicitThis: true