DDSXML — Minor typos, inconsistencies, and updates in specification document

The specification includes a number of typos that should be fixed:

• On Table 7.2, the caption should be "Supported XML Attribute Values" instead of "Supported XML Element Values"
• In section 7.1.3.2.1 Using Schema Files with Different Namespaces fix closing tag of "datareader_qos", which is incorrectly labeled as "dateader_qos".
• In section 7.2.3.1, the type of the "kind" element should be "historyKind" instead of "dds:historyKind".
• In section 7.2.4.2.1, rename "Binary" simpleType as "ddsBinary" and change the value element's type to "ddsBinary".
• In section 7.3.4.4.1.1 change the topic name from "FisrstTopic" to "FirstTopic".

Moreover, the specification includes some inconsistencies:

• Section 7.1.1 states that the XML representation of DDS-related resources shall use <dds> as the root of every document; however, this is incompatible with the flexibility offered by building blocks. It is also incompatible with having a root for type representation such as <types>. We should simply remove this requirement.

Finally, some of the references are outdated and should be updated to the latest revision of the specifications:

• Update reference to the IDL standard to version 4.2.
• Update reference to the DDS-XTypes standard to version 1.2.

Fix minor typos and update specification references

This proposal fixes a number of typos in the specification document and updates outdated references to the latest revision of the specification they mention.