RLS crashes on a `Stdlib.Scanf.Scan_failure` error

After installed `reason-vscode` plugin, the Reason Language Server keeps crash with the same error:

```plaintext
Stdlib.Scanf.Scan_failure("scanf: bad input at char number 2: illegal escape character '.'")Raised at file "scanf.ml" (inlined), line 444, characters 18-40 Called from file "scanf.ml", line 1164, characters 4-75 Called from file "vendor/Json.re", line 327, characters 44-83 Called from file "vendor/Json.re", line 336, characters 16-25 Called from file "vendor/Json.re", line 456, characters 23-49 Called from file "vendor/Json.re", line 497, characters 25-41 Called from file "vendor/Json.re", line 505, characters 28-55 Called from file "vendor/Json.re", line 520, characters 25-52 Called from file "vendor/Json.re", line 465, characters 23-39 Called from file "vendor/Json.re", line 485, characters 25-51 Called from file "vendor/Json.re", line 497, characters 25-41 Called from file "vendor/Json.re", line 505, characters 28-55 Called from file "vendor/Json.re", line 505, characters 28-55 Called from file "vendor/Json.re", line 520, characters 25-52 Called from file "vendor/Json.re", line 528,...
```

Screenshot is also attached.

Reproduce the crash after installing the reason-vscode plugin, then inspect vendor/Json.re at the scanf-related locations shown in the stack trace. Trace the input that causes Stdlib.Scanf.Scan_failure and verify that the language server no longer crashes for the reported case.

Written by the indexing model from the issue text.