Tweak RankedMatch behaviour and fix bug in its comparison function

casting TestableFlag<T> to UnderlyingType<T> was going through bool
conversion... Not sure how things worked earlier.

src/flags.hh

@@ -37,6 +37,7 @@ struct TestableFlags
     Flags value;
     constexpr operator bool() const { return (UnderlyingType<Flags>)value; }
     constexpr operator Flags() const { return value; }
+    constexpr operator UnderlyingType<Flags>() const { return (UnderlyingType<Flags>)value; }
 
     bool operator==(const TestableFlags<Flags>& other) const { return value == other.value; }
     bool operator!=(const TestableFlags<Flags>& other) const { return value != other.value; }

src/ranked_match.cc

@@ -216,6 +216,8 @@ UnitTest test_ranked_match{[] {
     kak_assert(not (RankedMatch{"source", "so"} < RankedMatch{"source", "so"}));
     kak_assert(RankedMatch{"single/word", "wo"} < RankedMatch{"multiw/ord", "wo"});
     kak_assert(RankedMatch{"foo/bar/foobar", "foobar"} < RankedMatch{"foo/bar/baz", "foobar"});
+    kak_assert(RankedMatch{"delete-buffer", "db"} < RankedMatch{"debug", "db"});
+    kak_assert(RankedMatch{"create_task", "ct"} < RankedMatch{"constructor", "ct"});
 }};
 
 UnitTest test_used_letters{[]()

src/ranked_match.hh

@@ -37,11 +37,11 @@ private:
     {
         None = 0,
         // Order is important, the highest bit has precedence for comparison
-        OnlyWordBoundary = 1 << 0,
-        FirstCharMatch = 1 << 1,
-        Prefix = 1 << 2,
-        SingleWord = 1 << 3,
-        Contiguous = 1 << 4,
+        FirstCharMatch   = 1 << 0,
+        SingleWord       = 1 << 1,
+        Contiguous       = 1 << 2,
+        OnlyWordBoundary = 1 << 3,
+        Prefix           = 1 << 4,
         FullMatch        = 1 << 5,
     };