Fix the code snippets that demonstrate stepper.set_acceleration and stepper.set_deceleration, which both erroneously used the key "speed" instead of the correct "acceleration" and "deceleration".
* Missing colon
* update sun
* format fix and adaptation
* fix format
* fix format 2
* fix format 3
* fix format
* fix format
* fix format
* format fix
* revert title as heads
* rename image case-sensitive
* rename again
## Description:
#222
**Related issue (if applicable):** fixes <link to issue>
**Pull request in [esphome](https://github.com/esphome/esphome) with YAML changes (if applicable):** esphome/esphome#<esphome PR number goes here>
**Pull request in [esphome-core](https://github.com/esphome/esphome-core) with C++ framework changes (if applicable):** esphome/esphome-core#<esphome-core PR number goes here>
## Checklist:
- [x] Branch: `next` is for changes and new documentation that will go public with the next ESPHome release. Fixes, changes and adjustments for the current release should be created against `current`.
Co-authored-by: Otto Winter <otto@otto-winter.com>
