Fix broken links

Author: mpilgrem

doc/commands/build_command.md

@@ -936,7 +936,8 @@ All the following examples assume that:
     consequently, the project-level configuration will be determined by a
     `stack.yaml` file in the `global-project` directory in the
     [Stack root](../topics/stack_root.md) (for further information, see the
-    [YAML configuration](../configure/yaml_configuration.md) documentation); and
+    [YAML configuration](../configure/yaml/yaml_configuration.md)
+    documentation); and
 
 *   if `stack build` is commanded in a project directory, there is a
     `stack.yaml` file in that directory.

doc/tutorial/hello_world_example.md

@@ -42,10 +42,11 @@ to make more sense.
 After creating the project directory, and obtaining and populating the project
 template, Stack will initialise its own project-level configuration. For further
 information about setting paramaters to populate templates, see the YAML
-configuration [documentation](yaml_configuration.md#templates). For further
-information about initialisation, see the `stack init` command
-[documentation](#the-stack-init-command). The `stack new` and `stack init`
-commands have options and flags in common.
+configuration
+[documentation](../configure/yaml/yaml_configuration.md#templates). For further
+information about initialisation, see the
+[`stack init`](../commands/init_command.md) command documentation. The
+`stack new` and `stack init` commands have options and flags in common.
 
 !!! info