move comment to .h file

Summary: Move comment about the method's intention to .h file so that i can easily see it in vscode

Reviewed By: kmancini

Differential Revision: D49428873

fbshipit-source-id: d20ac80581410fd6df341b7100be3616b82da593

watchman/root/watchlist.cpp

@@ -36,13 +36,6 @@ bool Root::removeFromWatched() {
   return false;
 }
 
-// Given a filename, walk the current set of watches.
-// If a watch is a prefix match for filename then we consider it to
-// be an enclosing watch and we'll return the root path and the relative
-// path to filename.
-// Returns NULL if there were no matches.
-// If multiple watches have the same prefix, it is undefined which one will
-// match.
 bool findEnclosingRoot(
     const w_string& fileName,
     w_string_piece& prefix,

watchman/root/watchlist.h

@@ -22,6 +22,13 @@ extern std::atomic<long> live_roots;
 extern folly::Synchronized<std::unordered_map<w_string, std::shared_ptr<Root>>>
     watched_roots;
 
+// Given a filename, walk the current set of watches.
+// If a watch is a prefix match for filename then we consider it to
+// be an enclosing watch and we'll return the root path and the relative
+// path to filename.
+// Returns NULL if there were no matches.
+// If multiple watches have the same prefix, it is undefined which one will
+// match.
 bool findEnclosingRoot(
     const w_string& fileName,
     w_string_piece& prefix,