Change title 'Accessing Public Methods'

Change title 'Accessing Public Methods' to 'Accessing Public Properties'.
Title 'Accessing Public Properties' more in relation with the content.
fixe tagline
bug #3441 [Expression]Change title 'Accessing Public Methods' (Pyrech)

This PR was submitted for the master branch but it was merged into the 2.4 branch instead (closes #3441).

Discussion
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[Expression]Change title 'Accessing Public Methods'

Change title 'Accessing Public Methods' to 'Accessing Public Properties' because it's more in relation with the content.

Commits
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b0e65e7 fixe tagline
8fc4ef8 Change title 'Accessing Public Methods'