-fprof-late and HasField leads to invalid json file
```haskell
{-# LANGUAGE DataKinds #-}
module Main where
import GHC.Records
main = print ()
data Person = Person { name :: String }
instance HasField "fullname" Person String where
getField = name
```
```
ghc Prof.hs -O -fprof-late -prof
./Prof +RTS -pj
```
Then looking in the json file you can see
```
{"id": 128, "label": "$fHasFieldSymbol"fullname"PersonList", "module": "Main", "src_loc": "Prof.hs:10:10-42", "is_caf": false},
```
which is not escaped properly.
cc @AndreasK
It seems that the escapeString function needs to be extended in `ProfilerReportJson.c`.
issue