RST reader: fix regression with code includes.

With the recent changes to include infrastructure,
included code blocks were getting an extra newline.

Closes #7436.  Added regression test.

pandoc.cabal

@@ -213,6 +213,7 @@ extra-source-files:
                  test/command/B.txt
                  test/command/C.txt
                  test/command/D.txt
+                 test/command/three.txt
                  test/command/01.csv
                  test/command/chap1/spider.png
                  test/command/chap2/spider.png

src/Text/Pandoc/Readers/RST.hs

@@ -474,6 +474,7 @@ includeDirective top fields body = do
            case lookup "literal" fields of
              Just _  -> B.rawBlock "rst" . sourcesToText <$> getInput
              Nothing -> parseBlocks
+  let isLiteral = isJust (lookup "code" fields `mplus` lookup "literal" fields)
   let selectLines =
         (case trim <$> lookup "end-before" fields of
                          Just patt -> takeWhile (not . (patt `T.isInfixOf`))
@@ -482,8 +483,11 @@ includeDirective top fields body = do
                          Just patt -> drop 1 .
                                         dropWhile (not . (patt `T.isInfixOf`))
                          Nothing   -> id)
+
   let toStream t =
-        toSources [(f, T.unlines . selectLines . T.lines $ t)]
+        Sources [(initialPos f,
+                   (T.unlines . selectLines . T.lines $ t) <>
+                    if isLiteral then mempty else "\n")]  -- see #7436
   currentDir <- takeDirectory . sourceName <$> getPosition
   insertIncludedFile parser toStream [currentDir] f startLine endLine
 

test/command/7436.md

@@ -0,0 +1,14 @@
+```
+% pandoc -f rst -t native
+.. include:: command/three.txt
+   :code:
+
+.. include:: command/three.txt
+   :literal:
+
+.. include:: command/three.txt
+^D
+[CodeBlock ("",[""],[("code","")]) "1st line.\n2nd line.\n3rd line.\n"
+,RawBlock (Format "rst") "1st line.\n2nd line.\n3rd line.\n"
+,Para [Str "1st",Space,Str "line.",SoftBreak,Str "2nd",Space,Str "line.",SoftBreak,Str "3rd",Space,Str "line."]]
+```

test/command/three.txt

@@ -0,0 +1,3 @@
+1st line.
+2nd line.
+3rd line.