FileConventions: fix WrapText function

Split paragraph based on codeblock positions so that codeblocks
with two lines, are not broken into multiple paragraphs.

Fixes nblockchain#117

src/FileConventions/Library.fs

@@ -244,9 +244,61 @@ let private WrapParagraph (text: string) (maxCharsPerLine: int) : string =
 
     processWords String.Empty String.Empty words
 
+let ExtractParagraphs(text: string) =
+    let lines = text.Split('\n') |> Seq.toList
+
+    let rec processLines
+        (remainingLines: List<string>)
+        (currentParagraph: List<string>)
+        (paragraphs: List<string>)
+        (insideCodeBlock: bool)
+        =
+        match remainingLines with
+        | [] ->
+            if currentParagraph <> [] then
+                List.singleton(String.Join("\n", List.rev currentParagraph))
+                @ paragraphs
+            else
+                paragraphs
+        | line :: rest ->
+            if String.IsNullOrWhiteSpace(line) then
+                if insideCodeBlock then
+                    processLines
+                        rest
+                        (line :: currentParagraph)
+                        paragraphs
+                        insideCodeBlock
+                else if currentParagraph <> [] then
+                    let newParagraph =
+                        String.Join("\n", List.rev currentParagraph)
+
+                    processLines
+                        rest
+                        []
+                        (newParagraph :: paragraphs)
+                        insideCodeBlock
+                else
+                    processLines rest [] paragraphs insideCodeBlock
+            elif line.Trim().StartsWith("```") then
+                let newInsideCodeBlock = not insideCodeBlock
+
+                processLines
+                    rest
+                    (line :: currentParagraph)
+                    paragraphs
+                    newInsideCodeBlock
+            else
+                processLines
+                    rest
+                    (line :: currentParagraph)
+                    paragraphs
+                    insideCodeBlock
+
+    List.rev <| processLines lines [] [] false
+
 let WrapText (text: string) (maxCharsPerLine: int) : string =
     let wrappedParagraphs =
-        text.Split $"{Environment.NewLine}{Environment.NewLine}"
+        ExtractParagraphs text
         |> Seq.map(fun paragraph -> WrapParagraph paragraph maxCharsPerLine)
 
     String.Join(