feat(cli): replace various format flags with --format={format}

docs/howto/load-task-locally.rst

@@ -55,15 +55,15 @@ For example, you can run:
 
 .. code-block:: shell
 
-   taskgraph morphed -J --tasks test-unit-py | jq -r 'to_entries | first | .value.task' | taskgraph load-task -
+   taskgraph morphed --format json --tasks test-unit-py | jq -r 'to_entries | first | .value.task' | taskgraph load-task -
 
 In this example, we're piping the definition of the task named ``test-unit-py``
 into ``taskgraph load-task``. This allows you to quickly iterate on the task
 and test that it runs as expected.
 
 .. note::
 
-   The output of ``taskgraph morphed -J`` looks something like:
+   The output of ``taskgraph morphed --format json`` looks something like:
 
    ``{ "<task id>": { "task": { <task definition> }}}``
 
@@ -103,7 +103,7 @@ by combining passing in a custom image locally, and piping a task definition via
 
 .. code-block:: shell
 
-   taskgraph morphed -J --tasks test-unit-py | jq -r 'to_entries | first | .value.task' | taskgraph load-task --image python -
+   taskgraph morphed --format json --tasks test-unit-py | jq -r 'to_entries | first | .value.task' | taskgraph load-task --image python -
 
 Developing in the Container
 ---------------------------

docs/howto/run-locally.rst

@@ -42,17 +42,18 @@ Useful Arguments
 Here are some useful arguments accepted by most ``taskgraph`` subcommands. For
 a full reference, see :doc:`/reference/cli`.
 
-``-J/--json``
-+++++++++++++
+``--format``
+++++++++++++
 
-By default only the task labels are displayed as output, but when ``-J/--json``
-is used, the full JSON representation of all task definitions are displayed.
+By default only the task labels are displayed as output, but when
+``--format json`` is used, the full JSON representation of all task definitions
+are displayed.
 
 .. note::
 
-   Using ``-J/--json`` can often result in a massive amount of output. Consider
-   using the ``--tasks`` and/or ``--target-kind`` flags in conjunction to
-   filter the result down to a manageable level.
+   Using ``--format json`` can often result in a massive amount of output.
+   Consider using the ``--tasks`` and/or ``--target-kind`` flags in conjunction
+   to filter the result down to a manageable level.
 
 ``--tasks/--tasks-regex``
 +++++++++++++++++++++++++
@@ -126,15 +127,15 @@ Validating Changes to Task Definitions
 
 If you're only modifying the definition of tasks, then you want to generate the
 ``full_task_graph``. This is because task definitions are frozen (with minor
-exceptions) after this phase. You'll also want to use the ``-J/--json`` flag and
+exceptions) after this phase. You'll also want to use ``--format json`` and
 likely also the ``--tasks`` flag to filter down the result.
 
 For example, let's say you modify a task called ``build-android``. Then you
 would run the following command:
 
 .. code-block:: shell
 
-   taskgraph full -J --tasks "build-android"
+   taskgraph full --format json --tasks "build-android"
 
 Then you can inspect the resulting task definition and validate that everything
 is configured as you expect.
@@ -148,7 +149,7 @@ If you're modifying *where* a task runs, e.g by changing a key that impacts the
 ``target_task_graph`` phase.
 
 Unlike when modifying the definition, we don't care about the contents of the
-task so passing the ``-J/--json`` flag is unnecessary. Instead, we can simply
+task so passing ``--format json`` is unnecessary. Instead, we can simply
 inspect whether the label exists or not. However it *is* important to make sure
 we're generating under the appropriate context(s) via the ``-p/--parameters``
 flag.

docs/index.rst

@@ -75,7 +75,7 @@ already, namely ``docker-image-linux`` and ``hello-world``.
 .. note::
 
    By default the ``taskgraph`` command will only output task labels. Try
-   adding ``--json`` to the command to see the actual definitions.
+   adding ``--format json`` to the command to see the actual definitions.
 
 See if you can create a new task by editing ``taskcluster/kinds/hello/kind.yml``,
 and re-run ``taskgraph full`` to verify.

docs/tutorials/creating-a-task-graph.rst

@@ -202,9 +202,9 @@ Now run:
 
 .. code-block:: bash
 
- taskgraph morphed -J
+ taskgraph morphed --format json
 
-The ``-J/--json`` flag will display the full JSON definition of your task.
+The ``--format json`` flag will display the full JSON definition of your task.
 Morphed is the final phase of :ref:`graph generation <graph generation>`, so
 represents your task's final form before it would get submitted to Taskcluster.
 In fact, if we hadn't made up the trust domain and worker pool in