Handles :file: option for code blocks to avoid warnings.

lib/packages/docutils/rst.nim

@@ -1520,6 +1520,10 @@ proc dirCodeBlock(p: var TRstParser, nimrodExtension = false): PRstNode =
   ## fake internal field to comminicate with the generator. The field is named
   ## ``default-language``, which is unlikely to collide with a field specified
   ## by any random rst input file.
+  ##
+  ## As an extension this proc will process the ``file`` extension field and if
+  ## present will replace the code block with the contents of the referenced
+  ## file.
   result = parseDirective(p, {hasArg, hasOptions}, parseLiteralBlock)
   var filename = strip(getFieldValue(result, "file"))
   if filename != "": 

lib/packages/docutils/rstgen.nim

@@ -786,6 +786,13 @@ proc parseCodeBlockField(d: PDoc, n: PRstNode, params: var CodeBlockParams) =
     var number: int
     if parseInt(n.getFieldValue, number) > 0:
       params.startLine = number
+  of "file":
+    # The ``file`` option is a Nimrod extension to the official spec, it acts
+    # like it would for other directives like ``raw`` or ``cvs-table``. This
+    # field is dealt with in ``rst.nim`` which replaces the existing block with
+    # the referenced file, so we only need to ignore it here to avoid incorrect
+    # warning messages.
+    discard
   of "default-language":
     params.langStr = n.getFieldValue.strip
     params.lang = params.langStr.getSourceLanguage