Support nvim-0.7's nvim_set_hl api

[EdenEast]

This pr adds support for nvim 0.7's new api nvim_set_hl. This pr also extends the compiler generate both a viml version and a nvim-0.7+ version. Nightfox will check if your editor is nvim-0.7+ before loading the correct precompiled file. When the user uses the compiler it also generates based on the editor's supported api.

Performance Note

From my initial testing there is no significant difference between the viml version and nvim_set_hi version when dealing with compiled files. Slightly more of the time the viml version is faster. I have tried to benchmark/time this with different methods:

• Startuptime with tweekmonster/startuptime.vim
• Startuptime with --startuptime
• Plenary with require('plenary.profile').benchmark()

Unsure that there is any benifit from this pr. It would be great of others could assist in coming up with a way to validate that nvim_set_hl version is faster.

Resolves: #131

[EdenEast]

Benchmarked requireing the two types of compiled files with the commited benchmark.

Benchmark

local benchmark = require("plenary.profile").benchmark
local fmt = string.format

local bench_iter = 100
local process_iter = 20

local function rep(n, char)
  local s = ""
  char = char or "-"
  for _ = 1, n do
    s = s .. char
  end
  return s
end

local function process(iterations)
  local function execute(modname)
    package.loaded[modname] = nil
    require(modname)
  end

  local nvim = benchmark(iterations, execute, "nightfox.precompiled.nvim.nightfox_compiled")
  local viml = benchmark(iterations, execute, "nightfox.precompiled.viml.nightfox_compiled")

  local difference = math.abs(nvim - viml)

  return nvim, viml, difference
end

local fmt_str = "| %-12s | %-12s | %-6s | %-12s |"
local lines = {}
table.insert(lines, fmt(fmt_str, "nvim", "viml", "winner", "difference"))
table.insert(lines, fmt(fmt_str, rep(12), rep(12), rep(6), rep(12)))
for _ = 1, process_iter do
  local nvim, viml, difference = process(bench_iter)
  local winner = viml > nvim and "nvim" or "viml"
  table.insert(lines, fmt(fmt_str, nvim, viml, winner, difference))
end

print(table.concat(lines, "\n"))

The results of this were:

nvim	viml	winner	difference
0.13587727	0.14480916	nvim	0.00893189
0.126019095	0.144379504	nvim	0.018360409
0.121695834	0.145396634	nvim	0.0237008
0.126382063	0.147077075	nvim	0.020695012
0.126739153	0.15228737	nvim	0.025548217
0.123327316	0.144052505	nvim	0.020725189
0.120775092	0.144650431	nvim	0.023875339
0.122740701	0.144309368	nvim	0.021568667
0.120412961	0.142972085	nvim	0.022559124
0.120056512	0.143038069	nvim	0.022981557
0.121483176	0.143661078	nvim	0.022177902
0.121731856	0.146417584	nvim	0.024685728
0.124857722	0.143044062	nvim	0.01818634
0.121358067	0.142138951	nvim	0.020780884
0.121309499	0.146483703	nvim	0.025174204
0.120200838	0.143400906	nvim	0.023200068
0.121330985	0.143589931	nvim	0.022258946
0.122106515	0.143682243	nvim	0.021575728
0.126486296	0.14283298	nvim	0.016346684
0.120689742	0.143274019	nvim	0.022584277

From this I can see a small marginal improvement.