Improve performance when syntax errors break entire files

[w0rp]

Often when editing certain file types, syntax errors introduced during editing towards the start of large files can slow down to the point where you have to disable ALE in order to continue editing a file. This is because certain tools behave poorly when a syntax error is encountered and file your entire file with errors. One approach we've taken in the past is to limit the amount of data that ALE will process. The problem with this approach is that the amount of data that a developer machine can process depends on the machine, and it requires too much configuration.

What we should do instead is add an optional setting for linter definitions to define a filter function which can be used for filtering the results of the loclist items either returned from LSP/tsserver, or from the linter's callback. This function can be used for any kind of filtering at all, and can immediately be used for slicing out all of the linter items up to the first problem that can be recognised as a syntax error. That way, all processing in ALE will stop on the first syntax error for specific linters, which will greatly improve performance.

[w0rp]

Superseded by #4208.