docs: Split out and merge C++ class hierarchy. (#6781)

This restructures the entry page for the C++ API documentation in
preparation for adding a quickstart and linking to examples and adding
more content.

3 files changed, 77 insertions, 58 deletions

diff --git a/docs/_static/custom.css b/docs/_static/custom.css
index a5403c295..9d07edeaf 100644
--- a/docs/_static/custom.css
+++ b/docs/_static/custom.css
@@ -87,3 +87,13 @@ a:hover, a:focus {
 .highlight .m {
   color: #ba2121;
 }
+
+#c-api-class-hierarchy code {
+  font-size: 100%;
+  font-weight: normal;
+  font-family: "Lato","proxima-nova","Helvetica Neue","Arial","sans-serif";
+}
+
+.hide-toctree {
+  display: none;
+}
diff --git a/docs/api/cpp/class_hierarchy.rst b/docs/api/cpp/class_hierarchy.rst
new file mode 100644
index 000000000..3fda2f348
--- /dev/null
+++ b/docs/api/cpp/class_hierarchy.rst
@@ -0,0 +1,45 @@
+C++ API Class Hierarchy
+=======================
+
+``namespace cvc5::api {``
+
+  * class :cpp:class:`CVC5ApiException <cvc5::api::CVC5ApiException>`
+  * class :cpp:class:`CVC5ApiRecoverableException <cvc5::api::CVC5ApiRecoverableException>`
+
+  * class :ref:`api/cpp/datatype:datatype`
+
+    * class :cpp:class:`const_iterator <cvc5::api::Datatype::const_iterator>`
+
+  * class :ref:`api/cpp/datatypeconstructor:datatypeconstructor`
+
+    * class :cpp:class:`const_iterator <cvc5::api::DatatypeConstructor::const_iterator>`
+
+  * class :ref:`api/cpp/datatypeconstructordecl:datatypeconstructordecl`
+  * class :ref:`api/cpp/datatypedecl:datatypedecl`
+  * class :ref:`api/cpp/datatypeselector:datatypeselector`
+
+  * class :ref:`api/cpp/grammar:grammar`
+
+  * class :ref:`api/cpp/kind:kind`
+
+  * class :ref:`api/cpp/op:op`
+
+  * class :ref:`api/cpp/result:result`
+
+    * enum :cpp:enum:`UnknownExplanation <cvc5::api::Result::UnknownExplanation>`
+
+  * class :ref:`api/cpp/roundingmode:roundingmode`
+
+  * class :ref:`api/cpp/solver:solver`
+
+  * class :ref:`api/cpp/sort:sort`
+
+  * class :cpp:class:`Stat <cvc5::api::Stat>`
+
+  * class :cpp:class:`Statistics <cvc5::api::Statistics>`
+
+  * class :ref:`api/cpp/term:term`
+
+    * class :cpp:class:`const_iterator <cvc5::api::Term::const_iterator>`
+
+``}``
diff --git a/docs/api/cpp/cpp.rst b/docs/api/cpp/cpp.rst
index 8d302d60c..17e121a2c 100644
--- a/docs/api/cpp/cpp.rst
+++ b/docs/api/cpp/cpp.rst
@@ -6,63 +6,27 @@ C++ API Documentation
 .. toctree::
   :maxdepth: 2
 
-  datatype
-  datatypeconstructor
-  datatypeconstructordecl
-  datatypedecl
-  datatypeselector
-  exceptions
-  grammar
-  kind
-  op
-  result
-  roundingmode
-  solver
-  sort
-  statistics
-  term
+  class_hierarchy
+
+.. container:: hide-toctree
+
+  .. toctree::
+    :maxdepth: 0
+
+    datatype
+    datatypeconstructor
+    datatypeconstructordecl
+    datatypedecl
+    datatypeselector
+    exceptions
+    grammar
+    kind
+    op
+    result
+    roundingmode
+    solver
+    sort
+    statistics
+    term
 
 
-Class Hierarchy
----------------
-
-* namespace ``cvc5::api``
-
-  * class :cpp:class:`CVC5ApiException <cvc5::api::CVC5ApiException>`
-  * class :cpp:class:`CVC5ApiRecoverableException <cvc5::api::CVC5ApiRecoverableException>`
-
-  * class :cpp:class:`Datatype <cvc5::api::Datatype>`
-
-    * class :cpp:class:`const_iterator <cvc5::api::Datatype::const_iterator>`
-
-  * class :cpp:class:`DatatypeConstructor <cvc5::api::DatatypeConstructor>`
-
-    * class :cpp:class:`const_iterator <cvc5::api::DatatypeConstructor::const_iterator>`
-  
-  * class :cpp:class:`DatatypeConstructorDecl <cvc5::api::DatatypeConstructorDecl>`
-  * class :cpp:class:`DatatypeDecl <cvc5::api::DatatypeDecl>`
-  * class :cpp:class:`DatatypeSelector <cvc5::api::DatatypeSelector>`
-
-  * class :cpp:class:`Grammar <cvc5::api::Grammar>`
-
-  * enum :cpp:enum:`Kind <cvc5::api::Kind>`
-  
-  * class :cpp:class:`Op <cvc5::api::Op>`
-
-  * class :cpp:class:`Result <cvc5::api::Result>`
-
-    * enum :cpp:enum:`UnknownExplanation <cvc5::api::Result::UnknownExplanation>`
-
-  * enum :cpp:enum:`RoundingMode <cvc5::api::RoundingMode>`
-  
-  * class :cpp:class:`Solver <cvc5::api::Solver>`
-
-  * class :cpp:class:`Sort <cvc5::api::Sort>`
-
-  * class :cpp:class:`Stat <cvc5::api::Stat>`
-
-  * class :cpp:class:`Statistics <cvc5::api::Statistics>`
-  
-  * class :cpp:class:`Term <cvc5::api::Term>`
-
-    * class :cpp:class:`const_iterator <cvc5::api::Term::const_iterator>`