A few more to do:

• reference/solr/solrdocument/reset.xml: <refpurpose>This is an alias to SolrDocument::clear()</refpurpose>
• reference/solr/solrparams/add.xml: <refpurpose>This is an alias for SolrParams::addParam</refpurpose>
• reference/solr/solrparams/get.xml: <refpurpose>This is an alias for SolrParams::getParam</refpurpose>

Note there are also &info.function.alias; and &info.method.alias; which are used for basically the same purpose. I guess we need to cater to these as well; maybe just replace them with &Alias;?

Yeah, I saw them, but I didn't touch them because they were luckily not used in the <refpurpose> tag. As these entities use a slightly different wording than &Alias;, I decided not to complicate my PR.

I didn't touch them because they were luckily not used in the <refpurpose> tag

Indeed. However, there are some case where they are used in the description, but there is no &Alias; in the refpurpuse, e.g. https://github.com/php/doc-en/blob/master/reference/curl/functions/curl-file-create.xml. I assume that needs to fixed.