chore(make): add task descriptions to Makefile.toml

[orhun]

All the tasks can be listed via cargo make --list-all-steps:

build - Compile the project
build-examples - Compile project examples
check - Check code for errors and warnings
ci - Run continuous integration tasks [aliases: default]
clippy - Run Clippy for linting
coverage - Generate code coverage report
fmt - Format source code
run-examples - Run project examples
style-check - Check code style
test - Run tests
test-backend - Run backend-specific tests
test-doc - Run documentation tests
test-windows - Run tests on Windows
typos - Run typo checks

[codecov]

Codecov Report

Merging #398 (74e59f3) into main (f63ac72) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main     #398   +/-   ##
=======================================
  Coverage   85.11%   85.11%           
=======================================
  Files          40       40           
  Lines        8736     8736           
=======================================
  Hits         7436     7436           
  Misses       1300     1300