[exec.run.loop] update run_loop count representation to use code format

[ericniebler]

[run.loop.members]/p2 ends with two periods.

i notice also that the whole [exec.run.loop] section is inconsistent about putting numbers in code font. this pr addresses the issue by uniformly applying \tcode to numbers.

[eisenwave]

The two-period issue seems to be fixed already. I'm not sure whether it's correct to use code font or not here.

Code font implies that an operation is performed with an int literal, and that isn't always what we want to express.

"is 0" in particular is almost guaranteed to be wrong, unless it's certain that whatever "is 0" is also of type int. It could be argued that 0ll "equals 0" or "is 0", but not that it "is 0".