docs(bigtable): small cleanups (#11610)

Exclude test proxy symbols from the documentation. Formatting as
monospace does not work well in titles. I tried backticks, `@c`
commands, and `<tt>`. Use the magic `*-endpoint-snippet` name to skip
pages from the DoxFX table of contents.

Author: coryan

google/cloud/bigtable/CMakeLists.txt

@@ -22,8 +22,15 @@ set(DOXYGEN_EXAMPLE_PATH
     "${CMAKE_CURRENT_SOURCE_DIR}/examples"
     "${CMAKE_CURRENT_SOURCE_DIR}/admin/samples"
     "${CMAKE_CURRENT_SOURCE_DIR}/quickstart")
-set(DOXYGEN_EXCLUDE_SYMBOLS "benchmarks" "bigtable_admin_internal"
-                            "bigtable_internal" "internal" "testing" "examples")
+set(DOXYGEN_EXCLUDE_SYMBOLS
+    "benchmarks"
+    "bigtable_admin_internal"
+    "bigtable_internal"
+    "internal"
+    "testing"
+    "examples"
+    "testproxy"
+    "test_proxy")
 
 include(GoogleCloudCppDoxygen)
 google_cloud_cpp_doxygen_targets("bigtable" DEPENDS cloud-docs

google/cloud/bigtable/doc/bigtable-main.dox

@@ -82,9 +82,11 @@ endpoint for `google::cloud::bigtable::Table`:
 
 @snippet client_samples.cc table-set-endpoint
 
-Follow these links for additional examples
- [BigtableTableAdminClient](@ref BigtableTableAdminClient-set-endpoint-snippet)
- [InstanceTableAdminClient](@ref BigtableInstanceAdminClient-set-endpoint-snippet)
+Changing the default endpoint for other `*Client` classes is very similar, as
+shown in these examples:
+
+- [BigtableTableAdminClient](@ref BigtableTableAdminClient-set-endpoint-snippet)
+- [InstanceTableAdminClient](@ref BigtableInstanceAdminClient-set-endpoint-snippet)
 */
 
 /**
@@ -101,9 +103,11 @@ Keep in mind that we chose this as an example because it is relatively easy to
 understand. Consult the [Best practices for managing service account keys]
 guide for more details.
 
-Follow these links for additional examples
- [BigtableTableAdminClient](@ref BigtableTableAdminClient-with-service-account-snippet)
- [InstanceTableAdminClient](@ref BigtableInstanceAdminClient-with-service-account-snippet)
+Changing the default authentication configuration for other `*Client` classes is
+very similar, as shown in these examples:
+
+- [BigtableTableAdminClient](@ref BigtableTableAdminClient-with-service-account-snippet)
+- [InstanceTableAdminClient](@ref BigtableInstanceAdminClient-with-service-account-snippet)
 
 Keep in mind that we chose this as an example because it is relatively easy to
 understand. Consult the [Best practices for managing service account keys]
@@ -117,32 +121,32 @@ guide for more details.
 
 */
 
-/*! @page Table-set-endpoint Override @c Table Default Endpoint
+/*! @page Table-set-endpoint-snippet Override Table Default Endpoint
 
 @snippet google/cloud/bigtable/examples/client_samples.cc table-set-endpoint
 */
 
-/*! @page Table-with-service-account-snippet Override @c Table Default Authentication
+/*! @page Table-with-service-account-snippet Override Table Default Authentication
 
 @snippet google/cloud/bigtable/examples/client_samples.cc table-with-service-account
 */
 
-/*! @page BigtableTableAdminClient-set-endpoint-snippet Override @c BigtableTableAdminClient Default Endpoint
+/*! @page BigtableTableAdminClient-set-endpoint-snippet Override BigtableTableAdminClient Default Endpoint
 
 @snippet google/cloud/bigtable/admin/samples/bigtable_table_admin_client_samples.cc set-client-endpoint
 */
 
-/*! @page BigtableTableAdminClient-with-service-account-snippet Override @c BigtableTableAdminClient Default Authentication
+/*! @page BigtableTableAdminClient-with-service-account-snippet Override BigtableTableAdminClient Default Authentication
 
 @snippet google/cloud/bigtable/admin/samples/bigtable_table_admin_client_samples.cc with-service-account
 */
 
-/*! @page BigtableInstanceAdminClient-set-endpoint-snippet Override @c BigtableInstanceAdminClient Default Endpoint
+/*! @page BigtableInstanceAdminClient-set-endpoint-snippet Override BigtableInstanceAdminClient Default Endpoint
 
 @snippet google/cloud/bigtable/admin/samples/bigtable_instance_admin_client_samples.cc set-client-endpoint
 */
 
-/*! @page BigtableInstanceAdminClient-with-service-account-snippet Override @c BigtableInstanceAdminClient Default Authentication
+/*! @page BigtableInstanceAdminClient-with-service-account-snippet Override BigtableInstanceAdminClient Default Authentication
 
 @snippet google/cloud/bigtable/admin/samples/bigtable_instance_admin_client_samples.cc with-service-account
 */

google/cloud/bigtable/doc/migrating-from-dataclient.dox

@@ -1,6 +1,6 @@
 /*!
 
-@page migrating-from-dataclient Migrating from `DataClient` to `DataConnection`
+@page migrating-from-dataclient Migrating from DataClient to DataConnection
 
 In this document we describe how to migrate existing code that uses `DataClient`
 to use `DataConnection`.