Markdown writer: omit space after opening code block fence

The CommonMark spec shows that it's not necessary to have a space
between the code fence and the language string:
https://spec.commonmark.org/0.29/#example-112
This also avoids a needless trailing space after a code fence that
does not include a language string.

Change-Id: I2addd38a196045a7442150760b73269bfe4ffb22
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>

src/gui/text/qtextmarkdownwriter.cpp

@@ -447,7 +447,7 @@ int QTextMarkdownWriter::writeBlock(const QTextBlock &block, bool wrap, bool ign
             m_codeBlockFence = QString(3, fenceChar.at(0));
             // A block quote can contain an indented code block, but not vice-versa.
             m_stream << m_linePrefix << QString(m_wrappedLineIndent, Space) << m_codeBlockFence
-                     << Space << blockFmt.stringProperty(QTextFormat::BlockCodeLanguage) << Newline;
+                     << blockFmt.stringProperty(QTextFormat::BlockCodeLanguage) << Newline;
             m_fencedCodeBlock = true;
         }
         wrap = false;

tests/auto/gui/text/qtextmarkdownwriter/data/blockquotes.md

@@ -20,7 +20,7 @@ MacFarlane writes:
 > equivalent sample of Markdown. Here is a sample of AsciiDoc from the AsciiDoc
 > manual:
 
-> ``` AsciiDoc
+> ```AsciiDoc
 > 1. List item one.
 > +
 > List item one continued with a second paragraph followed by an
@@ -50,7 +50,7 @@ Now let's have an indented code block:
     }
 
 and end with a fenced code block:
-~~~ pseudocode
+~~~pseudocode
 #include <something.h>
 #include <else.h>
 

tests/auto/gui/text/qtextmarkdownwriter/data/listsAndCodeBlocks.md

@@ -1,6 +1,6 @@
 - something happens in the debugger like this:
 
-  ``` 
+  ```
   1   QQuickEventPoint::setGrabberItem                 qquickevents.cpp     869 0x7ffff7a963f2 
   2   QQuickItem::grabMouse                            qquickitem.cpp      7599 0x7ffff7abea29 
   3   QQuickWindowPrivate::deliverMatchingPointsToItem qquickwindow.cpp    2738 0x7ffff7aea34c 
@@ -16,8 +16,8 @@
 
 - something I tried to fix it:
 
-  ``` 
-  code goes here, probably c++
+  ```c++
+  item->ungrab();
   ```
 - still didn't fix it, expecting a breakthrough any day now
 - some sort of miracle

tests/auto/gui/text/qtextmarkdownwriter/tst_qtextmarkdownwriter.cpp

@@ -432,7 +432,7 @@ void tst_QTextMarkdownWriter::fromHtml_data()
         "![foo](/url \"title\")\n\n";
     QTest::newRow("code") <<
         "<pre class=\"language-pseudocode\">\n#include \"foo.h\"\n\nblock {\n    statement();\n}\n\n</pre>" <<
-        "``` pseudocode\n#include \"foo.h\"\n\nblock {\n    statement();\n}\n```\n\n";
+        "```pseudocode\n#include \"foo.h\"\n\nblock {\n    statement();\n}\n```\n\n";
     // TODO
 //    QTest::newRow("escaped number and paren after double newline") <<
 //        "<p>(The first sentence of this paragraph is a line, the next paragraph has a number</p>13) but that's not part of an ordered list" <<