Enhance README section headers with emojis

Author: tiagocoutinho

README.md

@@ -46,7 +46,7 @@ $ pip install linuxpy --group=dev
 
 ## Subsystems
 
-### GPIO
+### GPIO ⚡
 
 ```python
 from linuxpy.gpio import Device
@@ -65,7 +65,7 @@ with Device.from_id(0) as gpio:
 Check the [GPIO user guide](https://tiagocoutinho.github.io/linuxpy/user_guide/gpio/) and
 [GPIO reference](https://tiagocoutinho.github.io/linuxpy/api/gpio/) for more information.
 
-### Input
+### Input 🕹️
 
 ```python
 import time
@@ -83,7 +83,7 @@ with pad:
 Check the [Input user guide](https://tiagocoutinho.github.io/linuxpy/user_guide/input/) and
 [Input reference](https://tiagocoutinho.github.io/linuxpy/api/input/) for more information.
 
-### Led
+### Led 💡
 
 ```python
 from linuxpy.led import find
@@ -96,7 +96,7 @@ print(caps_lock.max_brightness)
 Check the [LED user guide](https://tiagocoutinho.github.io/linuxpy/user_guide/led/) and
 [LED reference](https://tiagocoutinho.github.io/linuxpy/api/led/) for more information.
 
-### MIDI Sequencer
+### MIDI Sequencer 🎹
 
 ```console
 $ python
@@ -117,7 +117,7 @@ $ python
 Check the [MIDI user guide](https://tiagocoutinho.github.io/linuxpy/user_guide/midi/) and
 [MIDI reference](https://tiagocoutinho.github.io/linuxpy/api/midi/) for more information.
 
-### Thermal and cooling
+### Thermal and cooling 🌡️
 
 ```python
 from linuxpy.thermal import find
@@ -128,7 +128,7 @@ with find(type="x86_pkg_temp") as tz:
 Check the [Thermal and cooling user guide](https://tiagocoutinho.github.io/linuxpy/user_guide/thermal/) and
 [Thermal and cooling reference](https://tiagocoutinho.github.io/linuxpy/api/thermal/) for more information.
 
-### Video
+### Video 🎥
 
 Video for Linux 2 (V4L2) python library