docs: fix a few simple typos

[ccanepa]

There are small typos in:

• benchmarks/collision/compare_collisions.py
• cocos/actions/base_actions.py
• cocos/actions/instant_actions.py
• cocos/audio/pygame/mixer.py
• cocos/cocosnode.py
• cocos/custom_clocks.py
• cocos/mapcolliders.py
• cocos/particle.py
• cocos/skeleton.py
• cocos/text.py
• samples/jumping_lens.py
• samples/mouse_elastic_box_selection.py
• test/test_shader_examples.py
• utest/aux_RectMapCollider__no_stuck.py
• utest/test_RectMapCollider__no_stuck.py

Fixes:

• Should read unschedules rather than unchedules.
• Should read underlying rather than undelying.
• Should read callbacks rather than calllbacks.
• Should read parameterizable rather than parametrizable.
• Should read assigns rather than assings.
• Should read unconditionally rather than inconditionally.
• Should read specifying rather than specifing.
• Should read parameters rather than parameteres.
• Should read initialized rather than intialized.
• Should read hardcoded rather than harcoded.
• Should read function rather than funtion.
• Should read diagnostic rather than diagonostic.
• Should read decrease rather than decraese.
• Should read correction rather than correctioin.
• Should read between rather than betwen.
• Should read approach rather than aproach.

Closes #344