Add new description element (as a child of all document-link elements)

[dalepotter]

Add a new element at the following locations:

• iati-activities/iati-activity/document-link/description
• iati-organisations/iati-organisation/document-link/description

...with definition:

A description of the document contents, or guidance on where to access the relevant information in the document.

The element will have an occurrence rule of 0..1.

This will also add the following sub-attributes/elements with definitions:

• iati-activities/iati-activity/document-link/description/narrative and iati-organisations/iati-organisation/document-link/description/narrative - occurs 1..*, type xsd:string

  The free text name or description of the item being described. This can be repeated in multiple languages.

• iati-activities/iati-activity/document-link/description/narrative/@xml:lang and iati-organisations/iati-organisation/document-link/description/narrative/@xml:lang - occurs 0..1,

  A code specifying the language of text in this element.It is recommended that wherever possible only codes from ISO 639-1 are used.

Tasks:

• [x] Add test cases
• [x] Add iati-activities/iati-activity/document-link/description - Done in IATI/IATI-Schemas#372
• [x] Locate the narrative element in common to use - Done in IATI/IATI-Schemas#372
• [x] Add iati-activities/iati-activity/document-link/description/narrative - Done in IATI/IATI-Schemas#372
• [x] Add iati-activities/iati-activity/document-link/description/narrative/@xml:lang - Done in IATI/IATI-Schemas#372
• [x] Update Codelist mapping file for iati-activities/iati-activity/document-link/description/narrative/@xml:lang (to reference this attribute to the Language codelist) - Not needed, as paths for all xml:lang attributes already exist
• [x] Add iati-organisations/iati-organisation/document-link/description - Done in IATI/IATI-Schemas#372
• [x] Add iati-organisations/iati-organisation/document-link/description/narrative - Done in IATI/IATI-Schemas#372
• [x] Add iati-organisations/iati-organisation/document-link/description/narrative/@xml:lang - Done in IATI/IATI-Schemas#372
• [x] Update Codelist mapping file for iati-organisations/iati-organisation/document-link/description/narrative/@xml:lang (to reference this attribute to the Language codelist) - Not needed, as paths for all xml:lang attributes already exist