Add option to show symbol field name (as a prefix prior to field value string)

Description

I am trying to export boms for three variants of the schematics (5 / 10 / 15V), where different resistor values for each variant is filled inside associated field (Var_5V / Var_10V / Var_15V). The problem is, that it is not clear to which field any of three resistor value strings (field content) belongs to. Adding option to show field name as a prefix to fields content string on the canvas (and exported pdf) would make this problem to vanish.

Steps to reproduce

1. Have many (three at least) fields for a symbol;
2. Try to distinguish between each other in schematics;
3. Having option to see automatically add field name as a prefix to field value would help a lot.

KiCad Version

Application: KiCad Schematic Editor (64-bit)

Version: (6.99.0-1732-g4cd48cd5c9), release build

Libraries:
	wxWidgets 3.1.5
	FreeType 2.11.1
	HarfBuzz 2.8.2
	FontConfig 2.13.1
	libcurl/7.78.0-DEV Schannel zlib/1.2.11

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

Build Info:
	Date: Apr 24 2022 07:18:28
	wxWidgets: 3.1.5 (wchar_t,wx containers)
	Boost: 1.76.0
	OCC: 7.6.0
	Curl: 7.78.0-DEV
	ngspice: 36
	Compiler: Visual C++ 1929 without C++ ABI

Build settings:
	KICAD_USE_OCC=ON
	KICAD_SPICE=ON