Remove class title underline from operator template

[PProfizi]

Following changes made to fix problems in the API documentation.

As mentioned here, changes were made directly to the operator modules despite them being generated automatically upon server sync. This currently creates merge conflicts in the server sync pipeline (see here and conflicting files here).
This PR removes the conflict by updating the template used when generating the modules so they match with the expected format.

[PProfizi]

@moe-ad @jorgepiloto how should I mark the operators modules (everything under a folder in src/ansys/dpf/core/operators) as not to be edited directly?
I can mark them as requiring approval from maintainers as it is done for src/ansys/dpf/gate/ or src/ansys/grpc/dpf yet that is not exactly the same thing. It will only allow maintainers to spot this and tell the developer not to do that.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 88.42%. Comparing base (b7f89f7) to head (a051694).
Report is 1 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #1985   +/-   ##
=======================================
  Coverage   88.41%   88.42%           
=======================================
  Files          89       89           
  Lines       10258    10251    -7     
=======================================
- Hits         9070     9064    -6     
+ Misses       1188     1187    -1     

[moe-ad]

Hello @PProfizi. Welcome back! Thanks for identifying this.
Regarding your question, we can add a pre-commit hook that will not allow commits containing changes to that directory by any author/committer other than the one configured for the CI action that automatically generates those files.
Maybe @jorgepiloto can also have a different suggestion.

[moe-ad]

LGTM!