Eeschema Wishlist -> ERC error for label connected to only one pin.

Description

There should be a chance of having a warning or an error for labels connected only to a pin. This way I can identify if I haven't connected any pins in the schematic.

Steps to reproduce

Make a new project.
In Eeschema add a connector
Add different labels for each pin of the connector.
Run ERC I have no warnings and cannot set warnings for this label configuration possibility.

KiCad Version

Application: Eeschema

Version: (5.99.0-8513-g351074cc48), release build

Libraries:
	wxWidgets 3.0.5
	libcurl/7.71.0 OpenSSL/1.1.1g (Schannel) zlib/1.2.11 brotli/1.0.7 libidn2/2.3.0 libpsl/0.21.0 (+libidn2/2.3.0) libssh2/1.9.0 nghttp2/1.41.0

Platform: Windows 10 (build 19042), 64-bit edition, 64 bit, Little endian, wxMSW

Build Info:
	Date: Jan 19 2021 21:57:44
	wxWidgets: 3.0.5 (wchar_t,wx containers,compatible with 2.8)
	Boost: 1.73.0
	OCE: 6.9.1
	Curl: 7.71.0
	ngspice: 32
	Compiler: GCC 10.2.0 with C++ ABI 1014

Build settings:
	KICAD_SCRIPTING=ON
	KICAD_SCRIPTING_MODULES=ON
	KICAD_SCRIPTING_PYTHON3=OFF
	KICAD_SCRIPTING_WXPYTHON=ON
	KICAD_SCRIPTING_WXPYTHON_PHOENIX=OFF
	KICAD_SCRIPTING_ACTION_MENU=ON
	KICAD_USE_OCE=ON
	KICAD_SPICE=ON

Edited Jan 20, 2021 by Jeff Young