[hardware_interface::RobotHW] doc: update read and write, fix: group …

[bmagyar]

…names (#444)

• doc: update read and write, fix: group names

• update brief and detailes of read and write methods

• fix doxygen group names

• remove too many details of class description -> new PR

• remove too many details of init method -> new PR

• apply suggestions from code review

• add doxygen group name "Control Loop" to read and write methods. Removes these methods from group Hardware Interface Switching

Co-Authored-By: Matt Reynolds mtreynolds@uwaterloo.ca

• Update hardware_interface/include/hardware_interface/robot_hw.h

add "is" from suggestion

Co-Authored-By: Matt Reynolds mtreynolds@uwaterloo.ca

• Add sugestions from code review to robot_hw.h

• Remove whitespaces

• Remove newline

• Add periods to briefs

• Add "is" to docstring

Co-Authored-By: Matt Reynolds mtreynolds@uwaterloo.ca

• remove trailing space

Co-authored-by: Matt Reynolds mtreynolds@uwaterloo.ca