docs/speed_python: Generalize "Floating point" subsection.
docs/speed_python: Generalize "Floating point" subsection.

Don't describe just single port's peculiarities, note aboute possible
array of issues with floating-point.

deshipu/micropython,PappaPeppar/micropython,dxxb/micropython,emfcamp/micropython,swegener/micropython,tralamazza/micropython,bvernoux/micropython,mpalomer/micropython,swegener/micropython,oopy/micropython,kerneltask/micropython,alex-march/micropython,TDAbboud/micropython,MrSurly/micropython-esp32,misterdanb/micropython,deshipu/micropython,oopy/micropython,pozetroninc/micropython,henriknelson/micropython,bvernoux/micropython,turbinenreiter/micropython,TDAbboud/micropython,trezor/micropython,swegener/micropython,misterdanb/micropython,PappaPeppar/micropython,tobbad/micropython,selste/micropython,pfalcon/micropython,mhoffma/micropython,matthewelse/micropython,oopy/micropython,tralamazza/micropython,cwyark/micropython,blazewicz/micropython,turbinenreiter/micropython,Peetz0r/micropython-esp32,tobbad/micropython,redbear/micropython,HenrikSolver/micropython,chrisdearman/micropython,alex-robbins/micropython,kerneltask/micropython,trezor/micropython,chrisdearman/micropython,deshipu/micropython,micropython/micropython-esp32,torwag/micropython,selste/micropython,tuc-osg/micropython,puuu/micropython,matthewelse/micropython,lowRISC/micropython,mpalomer/micropython,pramasoul/micropython,bvernoux/micropython,emfcamp/micropython,alex-march/micropython,dmazzella/micropython,MrSurly/micropython,dmazzella/micropython,cwyark/micropython,blazewicz/micropython,misterdanb/micropython,ryannathans/micropython,MrSurly/micropython,adafruit/micropython,Timmenem/micropython,pozetroninc/micropython,pramasoul/micropython,turbinenreiter/micropython,pozetroninc/micropython,kerneltask/micropython,dxxb/micropython,hiway/micropython,tralamazza/micropython,misterdanb/micropython,Timmenem/micropython,swegener/micropython,hiway/micropython,praemdonck/micropython,HenrikSolver/micropython,mhoffma/micropython,torwag/micropython,TDAbboud/micropython,infinnovation/micropython,pfalcon/micropython,cwyark/micropython,henriknelson/micropython,infinnovation/micropython,chrisdearman/micropython,henriknelson/micropython,adafruit/circuitpython,jmarcelino/pycom-micropython,adafruit/micropython,ganshun666/micropython,ganshun666/micropython,emfcamp/micropython,bvernoux/micropython,selste/micropython,hiway/micropython,mhoffma/micropython,blazewicz/micropython,micropython/micropython-esp32,emfcamp/micropython,HenrikSolver/micropython,puuu/micropython,alex-robbins/micropython,mpalomer/micropython,pozetroninc/micropython,alex-robbins/micropython,oopy/micropython,Timmenem/micropython,micropython/micropython-esp32,infinnovation/micropython,HenrikSolver/micropython,dxxb/micropython,hiway/micropython,selste/micropython,TDAbboud/micropython,dinau/micropython,chrisdearman/micropython,AriZuu/micropython,matthewelse/micropython,MrSurly/micropython-esp32,Peetz0r/micropython-esp32,dinau/micropython,micropython/micropython-esp32,adafruit/circuitpython,MrSurly/micropython-esp32,trezor/micropython,henriknelson/micropython,Timmenem/micropython,adafruit/micropython,swegener/micropython,deshipu/micropython,drrk/micropython,selste/micropython,trezor/micropython,dinau/micropython,trezor/micropython,turbinenreiter/micropython,lowRISC/micropython,tralamazza/micropython,toolmacher/micropython,praemdonck/micropython,redbear/micropython,misterdanb/micropython,toolmacher/micropython,matthewelse/micropython,HenrikSolver/micropython,adafruit/circuitpython,SHA2017-badge/micropython-esp32,drrk/micropython,MrSurly/micropython-esp32,infinnovation/micropython,AriZuu/micropython,PappaPeppar/micropython,adafruit/micropython,puuu/micropython,matthewelse/micropython,ganshun666/micropython,cwyark/micropython,redbear/micropython,MrSurly/micropython,ryannathans/micropython,drrk/micropython,alex-march/micropython,dmazzella/micropython,SHA2017-badge/micropython-esp32,drrk/micropython,Peetz0r/micropython-esp32,drrk/micropython,jmarcelino/pycom-micropython,cwyark/micropython,hosaka/micropython,torwag/micropython,oopy/micropython,alex-march/micropython,puuu/micropython,emfcamp/micropython,ryannathans/micropython,dxxb/micropython,SHA2017-badge/micropython-esp32,TDAbboud/micropython,ganshun666/micropython,micropython/micropython-esp32,Timmenem/micropython,hosaka/micropython,Peetz0r/micropython-esp32,hiway/micropython,blazewicz/micropython,AriZuu/micropython,toolmacher/micropython,puuu/micropython,ryannathans/micropython,tuc-osg/micropython,adafruit/circuitpython,MrSurly/micropython-esp32,MrSurly/micropython,AriZuu/micropython,pozetroninc/micropython,SHA2017-badge/micropython-esp32,ryannathans/micropython,dinau/micropython,tobbad/micropython,dinau/micropython,mhoffma/micropython,tuc-osg/micropython,jmarcelino/pycom-micropython,mpalomer/micropython,adafruit/circuitpython,mhoffma/micropython,tuc-osg/micropython,deshipu/micropython,alex-robbins/micropython,hosaka/micropython,alex-march/micropython,praemdonck/micropython,chrisdearman/micropython,AriZuu/micropython,lowRISC/micropython,lowRISC/micropython,tobbad/micropython,toolmacher/micropython,matthewelse/micropython,adafruit/micropython,redbear/micropython,mpalomer/micropython,hosaka/micropython,tuc-osg/micropython,dxxb/micropython,SHA2017-badge/micropython-esp32,kerneltask/micropython,toolmacher/micropython,MrSurly/micropython,kerneltask/micropython,adafruit/circuitpython,pfalcon/micropython,alex-robbins/micropython,PappaPeppar/micropython,pramasoul/micropython,henriknelson/micropython,blazewicz/micropython,infinnovation/micropython,torwag/micropython,tobbad/micropython,Peetz0r/micropython-esp32,praemdonck/micropython,torwag/micropython,pramasoul/micropython,lowRISC/micropython,dmazzella/micropython,pfalcon/micropython,jmarcelino/pycom-micropython,jmarcelino/pycom-micropython,redbear/micropython,hosaka/micropython,pramasoul/micropython,ganshun666/micropython,pfalcon/micropython,praemdonck/micropython,PappaPeppar/micropython,bvernoux/micropython,turbinenreiter/micropython