Forward slash in a symbol name corrupts symbol library.

Description

Having a forward slash "/" in a symbol's name corrupts the symbol library.

Steps to reproduce

1. Create a new symbol in an important symbol library.
2. Add a "/" in its name.
3. Close the symbol editor.
4. Reopen the symbol editor. An error pops.
5. Open the library to see a lot of symbols have now disappeared.
6. Use the backup library to restore this tragedy.

KiCad Version

Application: KiCad

Version: 6.0.6-3a73a75311~116~ubuntu20.04.1, release build

Libraries:
	wxWidgets 3.0.4
	libcurl/7.68.0 OpenSSL/1.1.1f zlib/1.2.11 brotli/1.0.7 libidn2/2.2.0 libpsl/0.21.0 (+libidn2/2.2.0) libssh/0.9.3/openssl/zlib nghttp2/1.40.0 librtmp/2.3

Platform: Linux 5.13.0-51-generic x86_64, 64 bit, Little endian, wxGTK, ubuntu, x11

Build Info:
	Date: Jun 20 2022 15:49:56
	wxWidgets: 3.0.4 (wchar_t,wx containers,compatible with 2.8) GTK+ 3.24
	Boost: 1.71.0
	OCC: 7.5.2
	Curl: 7.83.1
	ngspice: 36
	Compiler: GCC 9.4.0 with C++ ABI 1013

Build settings:
	KICAD_USE_OCC=ON
	KICAD_SPICE=ON