Backport the equals and not equals substitutions

[suchetanrs]

Hello,

This PR backports the equals and not equals substitutions to humble along with their tests.

Update:
More information:

This is a backport of the PR #649

[SteveMacenski]

@christophebedard can we get a review and CI job for this?

[ahcorde]

Pulls: #864
Gist: https://gist.githubusercontent.com/ahcorde/7b0f380bf94595cae9edd62a5f2f0554/raw/3b6e4f5aff2be28bffe9936f28f46ca9352ba344/ros2.repos
BUILD args: --packages-above-and-dependencies launch
TEST args: --packages-above launch
ROS Distro: humble
Job: ci_launcher
ci_launcher ran: https://ci.ros2.org/job/ci_launcher/15887

• Linux
• Linux-aarch64
• Linux-rhel
• Windows

[christophebedard]

Looks good to me.

It's useful to link to the original PR in the PR description when making a backport: #649 (partial backport in this case).

[ahcorde]

• Linux
• Linux-aarch64
• Linux-rhel
• Windows

[emersonknapp]

I don't want to devalue effort that @suchetanrs has put in, but I also want to maintain branch cohesion as much as possible so that future backports remain easier. I might suggest we go with #871 instead of this PR, it is a complete cherry-pick backport of the original contribution. It backports the same substitutions but also the All and Any ones which were in #649. It leaves in the 1 and 0 boolean values in the test suite, which are possible with the backport in #872

Either that or I can follow up with #871 to fill in the remaining features that weren't backported here.

[christophebedard]

It's up to you guys

[suchetanrs]

I agree with @emersonknapp that #871 is a full backport and is more feature complete than this PR. Please feel free to prefer #871 instead of this if the need be.