Fix OperatorPrecedence bug pattern flagged by error prone

OperatorPrecedence bug pattern was extended recently to also suggest
disambiguation of logical and ternary operators. To avoid confusion,
that this could be a false positive, the documentation for this bug
patter was adjusted as well:

The explicit operator precedence using parens:

boolean e = (a || b) ? c : d;

should be prefered to implicit operator precedence:

boolean e = a || b ? c : d;

The intent is that it makes it easier to read, which is of course
subjectiver. The Google style guide: [2] suggests adding parens unless
"there is no reasonable chance the code will be misinterpreted without
them" and adds: "It is not reasonable to assume that every reader has
the entire Java operator precedence table memorized."

[1] https://github.com/google/error-prone/commit/39d288437add5c0b47f78b00d44c158259b86adf
[2] https://google.github.io/styleguide/javaguide.html#s4.7-grouping-parentheses

Details: https://errorprone.info/bugpattern/OperatorPrecedence
Release-Notes: skip
Change-Id: I41fc2f20f19c48bf35fdeaadcc347b3a8390c934