Remove frozen index glossary terms (elastic#1658)

elastic/elasticsearch#72946 marks the freeze API
as deprecated. This removes a couple of glossary terms related to frozen
indices.

Relates to elastic/elasticsearch#72990.

Author: jrodewig

docs/en/glossary/glossary.asciidoc

@@ -505,18 +505,6 @@ include::{es-repo-dir}/glossary.asciidoc[tag=follower-index-def]
 include::{es-repo-dir}/glossary.asciidoc[tag=force-merge-def]
 --
 
-[[glossary-freeze]] freeze::
-+
---
-include::{es-repo-dir}/glossary.asciidoc[tag=freeze-def]
---
-
-[[glossary-frozen-index]] frozen index::
-+
---
-include::{es-repo-dir}/glossary.asciidoc[tag=frozen-index-def]
---
-
 [[glossary-frozen-phase]] frozen phase::
 +
 --