feat(cli): add render command as alias to manim render (#317)

* feat(cli): add render command as alias to `manim render`

* feat(cli): add render command as alias to `manim render`

* chore(test): add test

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* chore(lib): simplify how ManimGL rendering is called

* chore(lib): test

* chore(ci): try identify error

* wip

* chore(test): add result output

* try: checkout

* Revert "try: checkout"

This reverts commit 60985f0b612ca0c6bff9726ebcccf07b1b1c4832.

* fix(deps): don't update lock

* chore(lib): simplify code and improve usage

* chore(cli): better cli

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* fix: does this fix?

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

manim_slides/docs/manim_slides_directive.py

@@ -69,6 +69,7 @@ render scenes that are defined within doctests, for example::
         >>> class DirectiveDoctestExample(Slide):
         ...     def construct(self):
         ...         self.play(Create(dot))
+        ...
 
 A third application is to render scenes from another specific file::