src/preprocessor.h: fixed comment.

removeParantheses() doesn't throws exception.

Correction for 1a48f869c8 commit.

No code change.

src/preprocessor.h

@@ -103,7 +103,6 @@ protected:
      * Remove redundant parantheses from preprocessor commands. This should only be called from read().
      * @param str Code processed by read().
      * @return code with reduced parantheses
-     * @throws std::runtime_error when code contains unhandled characters
      */
     static std::string removeParantheses(const std::string &str);