Added linting support for ldc2 and gdc compilers (zyedidia#3892)

* Added linting support for ldc2 and gdc compilers

* Update runtime/plugins/linter/linter.lua

ldc2 arguments have been updated for linter

Co-authored-by: Mikko <[email protected]>

---------

Co-authored-by: Mikko <[email protected]>

Author: kodesettings

runtime/plugins/linter/help/linter.md

@@ -8,6 +8,8 @@ following filetypes and linters:
 * **c**: gcc
 * **c++**: g++
 * **d**: dmd
+* **d**: ldc2
+* **d**: gdc
 * **go**: go build
 * **go**: go vet
 * **haskell**: hlint

runtime/plugins/linter/linter.lua

@@ -68,6 +68,8 @@ function preinit()
     makeLinter("gcc", "c", "gcc", {"-fsyntax-only", "-Wall", "-Wextra", "%f"}, "%f:%l:%c:.+: %m")
     makeLinter("g++", "c++", "g++", {"-fsyntax-only","-Wall", "-Wextra", "%f"}, "%f:%l:%c:.+: %m")
     makeLinter("dmd", "d", "dmd", {"-color=off", "-o-", "-w", "-wi", "-c", "%f"}, "%f%(%l%):.+: %m")
+    makeLinter("ldc2", "d", "ldc2", {"--o-", "--vcolumns", "-w", "-c", "%f"}, "%f%(%l,%c%):[^:]+: %m")
+    makeLinter("gdc", "d", "gdc", {"-fsyntax-only","-Wall", "-Wextra", "%f"}, "%f:%l:%c:.+: %m")
     makeLinter("eslint", "javascript", "eslint", {"-f","compact","%f"}, "%f: line %l, col %c, %m")
     makeLinter("gobuild", "go", "go", {"build", "-o", devnull, "%d"}, "%f:%l:%c:? %m")
     makeLinter("govet", "go", "go", {"vet"}, "%f:%l:%c: %m")