fixes docgen regression: don't add newLine for code if it's the first line (#23154)

Before (devel)


![image](https://github.com/nim-lang/Nim/assets/43030857/cde37109-027a-46c1-a37e-1d6062e6c609)

After (this PR and stable)


![image](https://github.com/nim-lang/Nim/assets/43030857/3366877c-7223-4749-a584-fe93f731281f)

It now keeps the same behavior as before

1 files changed, 4 insertions, 1 deletions

diff --git a/lib/packages/docutils/rst.nim b/lib/packages/docutils/rst.nim
index 9af163e15..a51ee49a6 100644
--- a/lib/packages/docutils/rst.nim
+++ b/lib/packages/docutils/rst.nim
@@ -1603,6 +1603,7 @@ proc parseMarkdownCodeblock(p: var RstParser): PRstNode =
   else:
     args = nil
   var n = newLeaf("")
+  var isFirstLine = true
   while true:
     if currentTok(p).kind == tkEof:
       rstMessage(p, meMissingClosing,
@@ -1614,7 +1615,8 @@ proc parseMarkdownCodeblock(p: var RstParser): PRstNode =
       inc p.idx, 2
       break
     elif currentTok(p).kind == tkIndent:
-      n.text.add "\n"
+      if not isFirstLine:
+        n.text.add "\n"
       if currentTok(p).ival > baseCol:
         n.text.add " ".repeat(currentTok(p).ival - baseCol)
       elif currentTok(p).ival < baseCol:
@@ -1624,6 +1626,7 @@ proc parseMarkdownCodeblock(p: var RstParser): PRstNode =
     else:
       n.text.add(currentTok(p).symbol)
       inc p.idx
+    isFirstLine = false
   result.sons[0] = args
   if result.sons[2] == nil:
     var lb = newRstNode(rnLiteralBlock)