Fixes a bug where we were looking for incorrect keys for metrics rules.
Previously, we were using full language names in the keys. Now, we use
the short language names in the metric ids. This is done through a
simplification of the code.
Also, this change does two smaller things:
1. Prints out the baseline count to the logs
2. Adds the `assertNever` function to ensure we never miss a case in
a switch statement. This function is borrowed from vscode-codeql.
The SARIF that we are interpreting has moved away from using `metric`
to the more general term, `rule`. We need to adapt our baseline lines of
code counting to use `rule` as well.
This change passes in a list of file types to the line counting
analysis. These are the languages for the databases being analyzed.
Line count analysis is restricted to these files.
This commit uses a third party library to estimate the lines of code in
a database that is to be analyzed by codeql.
The estimate uses the same includes and excludes globs for determining
which files should be counted.
The lines of code count is returned by language and injected into the
SARIF as `baseline` property in the `${language}/summary/lines-of-code`
metric.
