rm redundant blank lines before literal blocks (#18465)

lib/packages/docutils/rst.nim

@@ -1762,7 +1762,7 @@ proc parseLiteralBlock(p: var RstParser): PRstNode =
   var n = newLeaf("")
   if currentTok(p).kind == tkIndent:
     var indent = currentTok(p).ival
-    inc p.idx
+    while currentTok(p).kind == tkIndent: inc p.idx  # skip blank lines
     while true:
       case currentTok(p).kind
       of tkEof:

lib/packages/docutils/rstgen.nim

@@ -1258,7 +1258,7 @@ proc renderRstToOut(d: PDoc, n: PRstNode, result: var string) =
     doAssert false, "renderRstToOut"
   of rnLiteralBlock:
     renderAux(d, n, "<pre$2>$1</pre>\n",
-                    "\n\n\\begin{rstpre}\n$2\n$1\n\\end{rstpre}\n\n", result)
+                    "\n\n$2\\begin{rstpre}\n$1\n\\end{rstpre}\n\n", result)
   of rnQuotedLiteralBlock:
     doAssert false, "renderRstToOut"
   of rnLineBlock: