qdoc: no longer autolinks symbols that begin with "__"

qdoc no longer tries to autolink symbols that begin
with two underscores. There may be other cases where
qdoc should not try to autolink. They should be
handled in this same place.

Change-Id: I5a39ea2bb0edec2289b8a4b1a9af1f33534093a1
Task-number: QTBUG-42441
Reviewed-by: Topi Reiniö <topi.reinio@digia.com>

src/tools/qdoc/doc.cpp

@@ -1611,12 +1611,14 @@ void DocParser::parse(const QString& source,
                     QString word = in.mid(startPos, pos - startPos);
                     // is word a C++ symbol or an English word?
                     if ((numInternalUppercase >= 1 && numLowercase >= 2)
-                            || numStrangeSymbols >= 1) {
-                        append(Atom::AutoLink, word);
+                            || numStrangeSymbols > 0) {
+                        if (word.startsWith(QString("__")))
+                            appendWord(word);
+                        else
+                            append(Atom::AutoLink, word);
                     }
-                    else {
+                    else
                         appendWord(word);
-                    }
                 }
             }
         }