CODEOWNERS: make language coverage team responsible for more Rust and C++ code

Author: jketema

CODEOWNERS

@@ -24,8 +24,14 @@
 /rust/ @github/codeql-rust
 /rust/extractor/ @github/codeql-rust @github/code-scanning-language-coverage
 /shared/ @github/codeql-shared-libraries-reviewers
+/shared/cpp @github/code-scanning-language-coverage
+/shared/yeast @github/code-scanning-language-coverage
+/shared/yeast-macros @github/code-scanning-language-coverage
+/shared/yeast-schema @github/code-scanning-language-coverage
 /swift/ @github/codeql-swift
 /swift/extractor/ @github/codeql-swift @github/code-scanning-language-coverage
+/unified/extractor @github/code-scanning-language-coverage
+/unified/swift-syntax-rs @github/code-scanning-language-coverage
 /misc/codegen/ @github/codeql-swift
 /java/kotlin-extractor/ @github/codeql-kotlin @github/code-scanning-language-coverage
 /java/ql/test-kotlin1/ @github/codeql-kotlin