rm example, mutate string overload doesn't work and there is a better way

examples/fuzz_strtabs.nim

@@ -1,21 +0,0 @@
-import drchaos/mutator, std/[strtabs, random]
-
-proc mutate(data: var StringTableRef; sizeIncreaseHint: int; enforceChanges: bool; r: var Rand) =
-  var value: seq[tuple[key, value: string]]
-  for p in pairs(data):
-    value.add p
-  repeatMutateInplace(mutateSeq(value, tmp, 2, sizeIncreaseHint, r))
-  clear(data)
-  for key, val in value.items:
-    data[key] = val
-
-proc mutate(value: var string; sizeIncreaseHint: int; enforceChanges: bool; r: var Rand) =
-  repeatMutate(mutateUtf8String(move value, 4, sizeIncreaseHint, r))
-
-proc default(_: typedesc[StringTableRef]): StringTableRef =
-  newStringTable(modeCaseSensitive)
-
-func fuzzTarget(x: StringTableRef) =
-  doAssert x != {"key1": "val1", "key2": "val2"}.newStringTable
-
-defaultMutator(fuzzTarget)