Require explicit decorator on one arg constructors

We essentially follow this rule already, not relying on implicit
operators, although there are a number of cases where in theory we
could've implicitly constructed an object.

This commit enables the clang-tidy check.

Tested: Code compiles, passes clang-tidy.

Signed-off-by: Ed Tanous <edtanous@google.com>
Change-Id: Ia428463313b075c69614fdb326e8c5c094e7adde
diff --git a/http/utility.hpp b/http/utility.hpp
index 0b1743f..7b0af13 100644
--- a/http/utility.hpp
+++ b/http/utility.hpp
@@ -655,7 +655,8 @@
         return std::string_view(segment.data(), segment.size()) == expected;
     }
 
-    UrlSegmentMatcherVisitor(const boost::urls::string_value& segmentIn) :
+    explicit UrlSegmentMatcherVisitor(
+        const boost::urls::string_value& segmentIn) :
         segment(segmentIn)
     {}