docs: Fix doxygen link syntax

Author: rsomla1

doc/index.txt

@@ -5,17 +5,17 @@ MySQL Connector/C++ is a library for applications written in C or C++ that
 communicate with MySQL database servers. Version 8.0 of Connector/C++
 implements three different APIs which can be used by applications:
 
-- The new [X DevAPI] (@ref devapi_ref) for applications written in C++.
-- The new [X DevAPI for C] (@ref xapi_ref) for applications written in plain C.
-- The [legacy JDBC4-based API] (@ref jdbc_ref)
+- The new [X DevAPI](@ref devapi_ref) for applications written in C++.
+- The new [X DevAPI for C](@ref xapi_ref) for applications written in plain C.
+- The [legacy JDBC4-based API](@ref jdbc_ref)
   also implemented in version 1.1 of the connector.
 
-The new APIs give access to MySQL implementing a [document store]
-(https://dev.mysql.com/doc/refman/8.0/en/document-store.html). Internally
-these APIs use the new X Protocol to communicate with the MySQL Server.
-Consequently, code written against these APIs can work only with MySQL Server 8
-with the X Plugin enabled in it. Apart from accessing the document store, the
-new APIs allow executing traditional SQL queries as well.
+The new APIs give access to MySQL implementing a 
+[document store](https://dev.mysql.com/doc/refman/8.0/en/document-store.html). 
+Internally these APIs use the new X Protocol to communicate with the MySQL 
+Server. Consequently, code written against these APIs can work only with MySQL 
+Server 8 with the X Plugin enabled in it. Apart from accessing the document 
+store, the new APIs allow executing traditional SQL queries as well.
 
 Applications written against the JDBC4 based API of Connector/C++ 1.1 can be also
 compiled with Connector/C++ 8.0 which is backward compatible with the earlier
@@ -27,16 +27,16 @@ explained in @ref usage.
 
 More information:
 
-- [Connector/C++ X DevAPI Reference] (@ref devapi)
-- [Connector/C++ X DevAPI for C Reference] (@ref xapi)
+- [Connector/C++ X DevAPI Reference](@ref devapi)
+- [Connector/C++ X DevAPI for C Reference](@ref xapi)
 - [How to build code that uses Connector/C++](@ref usage)
-- [Indexing Document Collections] (@ref indexing)
+- [Indexing Document Collections](@ref indexing)
 
 See also our
-[online documentation] (https://dev.mysql.com/doc/connector-cpp/8.0/en/)
+[online documentation](https://dev.mysql.com/doc/connector-cpp/8.0/en/)
 
 <!--
-  Copyright (c) 2015, 2020, Oracle and/or its affiliates.
+  Copyright (c) 2015, 2022, Oracle and/or its affiliates.
 
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License, version 2.0, as

doc/xapi_ref.txt

@@ -82,7 +82,7 @@ There are several things to keep in mind:
 
 A more complete example of code that access MySQL Database using the X DevAPI
 for C is presented below. See also
-[the list of X DevAPI for C Functions] (@ref xapi).
+[the list of X DevAPI for C Functions](@ref xapi).
 
 
 ### Sample code which uses Connector/C++ with X DevAPI for C ###
@@ -253,7 +253,7 @@ Session closed
 
 
 <!--
-  Copyright (c) 2016, 2020, Oracle and/or its affiliates.
+  Copyright (c) 2016, 2022, Oracle and/or its affiliates.
 
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License, version 2.0, as