Improve SQL language landing pages

* And table of content moves

docs/src/main/sphinx/functions.md

@@ -4,14 +4,24 @@ This section describes the built-in SQL functions and operators supported by
 Trino. They allow you to implement complex capabilities and behavior of the
 queries executed by Trino operating on the underlying data sources.
 
-If you are looking for a specific function or operator, see the {doc}`full
-alphabetical list</functions/list>` or the {doc}`full list by
-topic</functions/list-by-topic>`. Using {doc}`SHOW FUNCTIONS
-</sql/show-functions>` returns a list of all available functions, including
-custom functions, with all supported arguments and a short description.
+Refer to the following sections for further details:
 
-Also see the {doc}`SQL data types</language>`
-and the {doc}`SQL statement and syntax reference</sql>`.
+* [SQL data types and other general aspects](/language)
+* [SQL statement and syntax reference](/sql)
+
+## Functions by name
+
+If you are looking for a specific function or operator by name use
+[](/sql/show-functions), or refer the to the following resources:
+
+:::{toctree}
+:maxdepth: 1
+
+functions/list
+functions/list-by-topic
+:::
+
+## Functions per topic
 
 ```{toctree}
 :maxdepth: 1
@@ -47,6 +57,4 @@ T-Digest            <functions/tdigest>
 URL                 <functions/url>
 UUID                <functions/uuid>
 Window              <functions/window>
-functions/list
-functions/list-by-topic
 ```

docs/src/main/sphinx/language.md

@@ -10,15 +10,22 @@ operations on the connected data source.
 This section provides a reference to the supported SQL data types and other
 general characteristics of the SQL support of Trino.
 
-A {doc}`full SQL statement and syntax reference<sql>` is
-available in a separate section.
+Refer to the following sections for further details:
+
+* [SQL statement and syntax reference](/sql)
+* [SQL functions and operators](/functions)
 
-Trino also provides {doc}`numerous SQL functions and operators<functions>`.
 
 ```{toctree}
 :maxdepth: 2
 
 language/sql-support
 language/types
+```
+
+```{toctree}
+:maxdepth: 1
+
 language/reserved
+language/comments
 ```

docs/src/main/sphinx/sql/comments.md → docs/src/main/sphinx/language/comments.md

@@ -23,4 +23,4 @@ SELECT * FROM table; -- This comment is ignored.
 
 ## See also
 
-[](./comment)
+[](/sql/comment)

docs/src/main/sphinx/sql.md

@@ -1,10 +1,12 @@
 # SQL statement syntax
 
-This section describes the SQL syntax used in Trino.
+This section describes the syntax for SQL statements that can be executed in
+Trino.
 
-A {doc}`reference to the supported SQL data types</language>` is available.
+Refer to the following sections for further details:
 
-Trino also provides {doc}`numerous SQL functions and operators<functions>`.
+* [SQL data types and other general aspects](/language)
+* [SQL functions and operators](/functions)
 
 ```{toctree}
 :maxdepth: 1
@@ -16,7 +18,6 @@ sql/alter-view
 sql/analyze
 sql/call
 sql/comment
-sql/comments
 sql/commit
 sql/create-materialized-view
 sql/create-role
@@ -44,7 +45,6 @@ sql/grant-roles
 sql/insert
 sql/match-recognize
 sql/merge
-sql/pattern-recognition-in-window
 sql/prepare
 sql/refresh-materialized-view
 sql/reset-session
@@ -78,3 +78,9 @@ sql/update
 sql/use
 sql/values
 ```
+
+```{toctree}
+:hidden:
+
+sql/pattern-recognition-in-window
+```

docs/src/main/sphinx/sql/comment.md

@@ -32,4 +32,4 @@ COMMENT ON COLUMN users.name IS 'full name';
 
 ## See also
 
-[](./comments)
+[](/language/comments)

docs/src/main/sphinx/sql/select.md

@@ -711,8 +711,7 @@ A window specification has the following components:
   consists of the rows matched by a pattern starting from that row.
   Additionally, if the frame specifies row pattern measures, they can be
   called over the window, similarly to window functions. For more details, see
-  {doc}`Row pattern recognition in window structures
-  </sql/pattern-recognition-in-window>`.
+  [Row pattern recognition in window structures](/sql/pattern-recognition-in-window) .
 
 Each window component is optional. If a window specification does not specify
 window partitioning, ordering or frame, those components are obtained from