Summary:
Fix style issues of yb_scan.c and yb_scan.h such that arc lint
errors/warnings are resolved.  Also do additional fixes not caught by
lint and some opinionated fixes as well.
Jira: DB-14384

Test Plan:
Close: #25198
Jenkins: compile only

Reviewers: tnayak

Reviewed By: tnayak

Subscribers: tnayak, yql

Differential Revision: https://phorge.dev.yugabyte.com/D40494