proper use of `xml:id` and `idref` attributes

[duncdrum]

The guidelines data contains a few wellformedness errors because of duplicate ids appearing inside <egXML> . This could be fixed, to help avoid leading editors on a path that adds duplicate ids by following the guidelines.

I also noticed eg.:

<placeName ref="ETH1085Aggabe" xml:id="aggabe"/> 

which should be

<placeName ref="#ETH1085Aggabe" xml:id="aggabe"/> 

it might be worth going over the guidelines to check for instances where problematic markup is presented as recommended practice.

wellformedness-report.txt

[eu-genia]

I only see this now
placeName ref="ETH1085Aggabe" is the way we do it, we only prefix # to target

The idea was to have examples copied 1:1 from the real records, we were told that passages inside egXML are treated separately, but if this is a problem we can change the xml:id values in the guidelines, but if anyhow possible it would be better not to.

E.g. in Persons.xml the passage

               <p>Changing the IDs to arrive at a certain visualization is deceptory as in the following example, where </p>
               <egXML xmlns="http://www.tei-c.org/ns/Examples">
                  <person sex="1" sameAs="wd:Q671055">
                     <persName xml:lang="en" xml:id="n1" type="main">Cyprian of Antioch</persName>
                     <persName xml:lang="gez" xml:id="n2">ቆጵርያኖስ፡</persName>
                     <persName xml:lang="gez" corresp="#n2" type="normalized">Qoṗrǝyānos</persName>
                  </person>
               </egXML>

               <p>The correct way to do this is</p>
               <egXML xmlns="http://www.tei-c.org/ns/Examples">
                  <person sex="1" sameAs="wd:Q671055">
                     <persName xml:lang="gez" xml:id="n1">ቆጵርያኖስ፡</persName>
                     <persName xml:lang="gez" corresp="#n1" type="normalized">Qoṗrǝyānos</persName>
                     <persName xml:lang="en" xml:id="n2" type="main">Cyprian of Antioch</persName>
                  </person>
               </egXML>
               <p>which will print in the application 'Cyprian of Antioch' instead of the usual first candidate 'Qoṗrǝyānos', the normalized transcription of the name in Fidal.</p>

would lose sense if we change xml:id in the second example