Improve warning wordings

[StrikerRUS]

Refer to #4724 (review).

@hzy46
Also, IMHO these two messages look contradictory:

LightGBM/src/io/dataset_loader.cpp

Line 838 in 5fbfa00

Log::Info("Recommend use integer for label index when loading data from binary for sanity check.");

LightGBM/src/io/dataset_loader.cpp

Line 842 in 5fbfa00

Log::Warning("Config label_column works only in case of loading data directly from text file. It will be ignored when loading from binary file.");

[jameslamb]

This looks good to me, thank you!

[StrikerRUS]

@hzy46 Could you please take a look at this?

Also, IMHO these two messages look contradictory:
#4731 (comment)

It seems to me suggesting using integer values for label index and then clarifying that any values will be simply ignored doesn't make a lot of sense. WDYT?

[shiyu1994]

@hzy46 Could you please take a look at this?

Also, IMHO these two messages look contradictory:
#4731 (comment)

It seems to me suggesting using integer values for label index and then clarifying that any values will be simply ignored doesn't make a lot of sense. WDYT?

For this case, maybe we can just skip the check for that label_idx_ is consistent? Since warning for a non-empty label_column is given subsequently here anyway.

[StrikerRUS]

Sounds reasonable to me. Can we make this in a follow-up PR to leave this one focused only on wordings?

[shiyu1994]

Sure.

[github-actions]

This pull request has been automatically locked since there has not been any recent activity since it was closed. To start a new related discussion, open a new issue at https://github.com/microsoft/LightGBM/issues including a reference to this.