Fix warning messages

[pvandyken]

All the warnings were displaying the wrong stack level: now corrected to show user code rather than snakebids code.

The warnings relating to bids were poorly worded or slightly inaccurate. These have been corrected

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (7558fc9) 91.61% compared to head (fe13caf) 91.62%.
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #377   +/-   ##
=======================================
  Coverage   91.61%   91.62%           
=======================================
  Files          39       39           
  Lines        1730     1731    +1     
=======================================
+ Hits         1585     1586    +1     
  Misses        145      145           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[kaitj]

Largely looks good to me - just wanted to clarify some wording in the warning message. It can get a little bit confusing when talking about both BIDS spec and snakebids` spec in the same message.

[kaitj]

The wording of this warning message is a little confusing to me. A few questions below that can hopefully clear some of this up:

• What does a "default BIDS spec" mean here (latest)?
• When talking about how "a spec has not been explictly declared", should this mention that we mean a snakebids' spec?
• Related to the previous comment, clarification of "default spec" and "future specs" though I think these may have more context given the mention of upgrading snakebids to start the sentence.

[pvandyken]

            wrn_msg = (
                f"Path generated with unrecognized entities, and a snakebids spec has"
                "not been explicitly declared. This could break in future snakebids "
                "versions, as the default spec can be changed without warning.\n"
                f"\tpath = {result!r}\n"
                f"\tentities = {custom_parts!r}\n\n"
                "Please declare a spec using:\n"
                "\tfrom snakebids import set_bids_spec\n"
                f'\tset_bids_spec("{specs.LATEST}")\n'
            ).expandtabs(4)

Less wordy. Hopefully "snakebids spec" is precise enough without needing a full definition, I think it's better to keep warning text brief. I could link the docs, but perhaps the code sample is enough?

[kaitj]

I think this looks good to me. I tink the code sample is probably enough here, we could always look into linking the docs if necessary if users raise an issue about it.

[pvandyken]

Also just fixed the error message for when multiple paths are found. That one's been bothering me for a while