common: Make use of [[nodiscard]] where applicable

Now that clang-format makes [[nodiscard]] attributes format sensibly, we
can apply them to several functions within the common library to allow
the compiler to complain about any misuses of the functions.

src/common/algorithm.h

@@ -15,7 +15,8 @@
 namespace Common {
 
 template <class ForwardIt, class T, class Compare = std::less<>>
-ForwardIt BinaryFind(ForwardIt first, ForwardIt last, const T& value, Compare comp = {}) {
+[[nodiscard]] ForwardIt BinaryFind(ForwardIt first, ForwardIt last, const T& value,
+                                   Compare comp = {}) {
     // Note: BOTH type T and the type after ForwardIt is dereferenced
     // must be implicitly convertible to BOTH Type1 and Type2, used in Compare.
     // This is stricter than lower_bound requirement (see above)