Improve logging for environment locking (#3792)
```
DEBUG Acquired lock for `.venv`
```
instead of
```
DEBUG Trying to lock if free: .venv/.lock
```
At trace level, this includes the pre-lock message as well
```
TRACE Checking lock for `.venv`
DEBUG Acquired lock for `.venv`
```
We'll still display the lock file path when something goes wrong
