Slightly better usability of exception messages

[alexey-milovidov]

Changelog category (leave one):

• Improvement

Changelog entry (up to few sentences, required except for Non-significant/Documentation categories):
Slightly better usability of error messages. Ask user not to remove the lines below Stack trace:.

[alexey-milovidov]

@stavrolia

milovidov@milovidov-nix:~/work/ClickHouse/dbms$ find . -name '*.h' -or -name '*.cpp' | xargs grep -F 'stack trace:'
./src/Storages/MergeTree/ReplicatedMergeTreeRestartingThread.cpp:            LOG_ERROR(log, "Couldn't start replication: " << e.what() << ", " << e.displayText() << ", stack trace:\n" << e.getStackTrace().toString());
./src/Storages/MergeTree/ReplicatedMergeTreeRestartingThread.cpp:            LOG_ERROR(log, "Couldn't start replication: " << e.what() << ", " << e.displayText() << ", stack trace:\n" << e.getStackTrace().toString());
./src/Databases/DatabaseOrdinary.cpp:        "Cannot create object '" + query.table + "' from query " + serializeAST(query) + ", error: " + e.displayText() + ", stack trace:\n"
./src/Databases/DatabaseOrdinary.cpp:                "Cannot parse definition from metadata file " + full_path + ", error: " + e.displayText() + ", stack trace:\n"
./src/Databases/DatabaseLazy.cpp:            ", stack trace:\n" + e.getStackTrace().toString(),

[alexey-milovidov]

Looks like you did not reviewed this PR properly.

Now you have to fix the following remaining things:

• the Stack trace text should always have capital S for consistency and the ease of grep;
• do not format the error message by yourself if getCurrentExceptionMessage or getExceptionMessage functions can be used - to lower the number of places in code where error message is formatted.

[stavrolia]

@alexey-milovidov, yeah, it’s a good idea to reduce the amount of copy paste here, see the follow up PR (#7936).

Could you clarify how I can improve my review process though? The present change looks good to me in isolation, and I don’t see any mistakes in review process.