Update planner

[classicrocker883]

Description

planner.h / planner.cpp

• Update doxygen comments, spacing

• Remove redundant public/private

• • ie: friend void do_homing_move is out of place

• Define unlike variables excplitly

• uint32_t max_acceleration_mm_per_s2[DISTINCT_AXES],

• min_segment_time_us;

• uint32_t max_acceleration_mm_per_s2[DISTINCT_AXES];

• uint32_t min_segment_time_us;

  
  <!--

Clearly describe the submitted changes with lots of details. Include images where helpful. Initial reviewers may not be familiar with the subject, so be as thorough as possible. You can use MarkDown syntax to improve readability with bullet lists, code blocks, and so on. PREVIEW and fix up formatting before submitting.

-->

Requirements

Benefits

• Use correct doxygen syntax
• Improve details of functions in comments, readability
• By defining variables explicitly, reduce errors when reading from EEPROM

Configurations

Related Issues

[thinkyhead]

We don't need to enforce Doxygen style comments in Marlin because we don't generate documentation or publish APIs for, e.g., the Planner class. Thus for comments on Marlin-specific methods and functions let's make it a general principle going forward to try to stick to human-readable formatting. Also, Doxygen formatting is less necessary from 2024 onward because we have LLMs and other tools that can derive the same information without the need for strict formatting.