fix corner case with custom pragma (#42)

The AST changes when you call the same custom pragma more than once.

confutils/config_file.nim

@@ -78,7 +78,20 @@ proc shortEnumName(n: NimNode): NimNode =
 proc traversePragma(pragma: NimNode):
     tuple[isCommandOrArgument: bool, defaultValue, namePragma: string] =
   pragma.expectKind nnkPragma
-  for child in pragma:
+  var child: NimNode
+
+  for childNode in pragma:
+    child = childNode
+
+    if child.kind == nnkCall:
+      # A custom pragma was used more than once (e.g.: {.pragma: posixOnly, hidden.}) and the
+      # AST is now:
+      # ```
+      # Call
+      #   Sym "hidden"
+      # ```
+      child = child[0]
+
     case child.kind
     of nnkSym:
       let sym = $child

tests/test_all.nim

@@ -10,7 +10,8 @@
 import
   test_ignore,
   test_config_file,
-  test_envvar
+  test_envvar,
+  test_pragma
 
 when defined(windows):
   import test_winreg

tests/test_pragma.nim

@@ -0,0 +1,27 @@
+import
+  std/unittest,
+  ../confutils,
+  ../confutils/defs
+
+{.pragma: customPragma, hidden.}
+
+type
+  TestConf* = object
+    statusBarEnabled* {.
+      customPragma
+      desc: "Display a status bar at the bottom of the terminal screen"
+      defaultValue: true
+      name: "status-bar" }: bool
+
+    statusBarEnabled2* {.
+      customPragma
+      desc: "Display a status bar at the bottom of the terminal screen"
+      defaultValue: true
+      name: "status-bar2" }: bool
+
+suite "test custom pragma":
+  test "funny AST when called twice":
+    let conf = TestConf.load()
+    doAssert(conf.statusBarEnabled == true)
+    doAssert(conf.statusBarEnabled2 == true)
+