Use asciidoctor's 'attribute-missing: warn' option and fix some places that were generating warnings because of unescaped/uninteded attribute syntax

solr/solr-ref-guide/build.xml

@@ -213,6 +213,7 @@
                    imagesDir="${build.content.dir}"
                    doctype="book"
                    safemode="unsafe">
+        <attribute key="attribute-missing" value="warn" />
         <attribute key="section-toc" value='' /><!-- we don't use these in the pdf -->
         <attribute key="icons" value="font" />
         <attribute key="icon-set" value="fa" />

solr/solr-ref-guide/src/_config.yml.template

@@ -91,6 +91,7 @@ asciidoctor:
   safe: 0
   attributes:
     <<: *solr-attributes-ref
+    attribute-missing: "warn"
     icons: "font"
     source-highlighter: "pygments"
     pygments-css: "style"

solr/solr-ref-guide/src/learning-to-rank.adoc

@@ -61,7 +61,7 @@ The LTR contrib module includes several feature classes as well as support for c
 |solr query |{solr-javadocs}/solr-ltr/org/apache/solr/ltr/feature/SolrFeature.html[SolrFeature] |`{"q":"{!func}` `recip(ms(NOW,last_modified)` `,3.16e-11,1,1)"}` |supported
 |solr filter query |{solr-javadocs}/solr-ltr/org/apache/solr/ltr/feature/SolrFeature.html[SolrFeature] |`{"fq":["{!terms f=category}book"]}` |supported
 |solr query + filter query |{solr-javadocs}/solr-ltr/org/apache/solr/ltr/feature/SolrFeature.html[SolrFeature] |`{"q":"{!func}` `recip(ms(NOW,last_modified),` `3.16e-11,1,1)",` `"fq":["{!terms f=category}book"]}` |supported
-|value |{solr-javadocs}/solr-ltr/org/apache/solr/ltr/feature/ValueFeature.html[ValueFeature] |`{"value":"${userFromMobile}","required":true}` |supported
+|value |{solr-javadocs}/solr-ltr/org/apache/solr/ltr/feature/ValueFeature.html[ValueFeature] |`{"value":"$\{userFromMobile}","required":true}` |supported
 |(custom) |(custom class extending {solr-javadocs}/solr-ltr/org/apache/solr/ltr/feature/Feature.html[Feature]) | |
 |===
 

solr/solr-ref-guide/src/meta-docs/pdf.adoc

@@ -141,5 +141,5 @@ These attributes use variables that are inserted by Ant during the PDF creation
 `<attribute key="solr-docs-version" value="${solr-docs-version}" />`:: The version of Solr covered by this guide.
 `<attribute key="solr-javadocs" value="${solr-javadocs}" />`:: Sets the path for Solr javadoc links to include the right path for the current release version.
 `<attribute key="lucene-javadocs" value="${lucene-javadocs}" />`:: Sets the path for Lucene javadoc links to the right path for the current release version.
-`<attribute key="build-date" value="${DSTAMP}" />`:: Sets the date of the build to add the date to the footer of each page of the PDF.
+`<attribute key="build-date" value="$\{DSTAMP}" />`:: Sets the date of the build to add the date to the footer of each page of the PDF.
 `<attribute key="build-year" value="${current.year}" />`:: Sets the year of the build to add the date to the copyright notice.

solr/solr-ref-guide/src/rule-based-replica-placement.adoc

@@ -84,7 +84,7 @@ Tag values come from a plugin called Snitch. If there is a tag named ‘rack’
 * *node*: node name
 * *role*: The role of the node. The only supported role is 'overseer'
 * *ip_1, ip_2, ip_3, ip_4*: These are ip fragments for each node. For example, in a host with ip `192.168.1.2`, `ip_1 = 2`, `ip_2 =1`, `ip_3 = 168` and` ip_4 = 192`
-* *sysprop.{PROPERTY_NAME}*: These are values available from system properties. `sysprop.key` means a value that is passed to the node as `-Dkey=keyValue` during the node startup. It is possible to use rules like `sysprop.key:expectedVal,shard:*`
+* *sysprop.\{PROPERTY_NAME}*: These are values available from system properties. `sysprop.key` means a value that is passed to the node as `-Dkey=keyValue` during the node startup. It is possible to use rules like `sysprop.key:expectedVal,shard:*`
 
 === How Snitches are Configured
 

solr/solr-ref-guide/src/uploading-structured-data-store-data-with-the-data-import-handler.adoc

@@ -306,7 +306,7 @@ For MySQL driver, which doesn't honor fetchSize and pulls whole resultSet, which
 +
 In this case, set `batchSize=-1` that pass setFetchSize(Integer.MIN_VALUE), and switch result set to pull row by row
 
-All of them substitute properties via `${placeholders}`.
+All of them substitute properties via `$\{placeholders}`.
 
 === URLDataSource