Update PREVENT_STUCK_MODIFIERS documentation in README

Cleanup after merge

- remove a superfluous parenthesis
- wrap lines longer than 80 characters
- add const specifiers where appropriate
- remove unnecessary casts

Merge branch 'modifier-release-fix' of https://github.com/eltang/qmk_firmware into modifier-release-fix

Update action.c

Update action.c

Update action.c

Update action.c

Update action.c

Update action.c

Update action.c

Update action.c

Update action.c

Update action.c

Update action.h

Update action.c

Update the memory consumption total value in README

Update the memory consumption of PREVENT_STUCK_MODIFIERS in README

Cut the memory consumption of PREVENT_STUCK_MODIFIERS in half

Expose the pressed_actions_cache global variable

Always provide an implementation of process_action_nocache