added slang linter support for systemverilog

lua/lint/linters/slang.lua

@@ -0,0 +1,19 @@
+local pattern = "^([^:]+):(%d+):(%d+): (%w+): (.+)"
+
+local groups = { "file", "lnum", "col", "severity", "message" }
+
+local severities = {
+  ["error"] = vim.diagnostic.severity.ERROR,
+  ["warning"] = vim.diagnostic.severity.WARN,
+}
+
+return {
+  cmd = "slang",
+  stdin = false,
+  stream = "stderr",
+  args = {
+    "-Weverything",
+  },
+  ignore_exitcode = false,
+  parser = require("lint.parser").from_pattern(pattern, groups, severities, { ["source"] = "slang" }),
+}