C#: Add telemetry query to report extractor information

[tamasvajk]

Sample results:

Key	Value
Number of files	2,020
Total number of lines	173,864
Number of lines of code	126,920
Number of files with extension config	1
Number of files with extension cs	1,562
Number of files with extension props	32
Number of files with extension dll	394
Number of files with extension csproj	30
Number of diagnostics with severity 0	7,303
Number of diagnostics with severity 2	12,611
Number of diagnostics with severity 3	762
Total number of lines with extension config	11
Total number of lines with extension cs	171,160
Total number of lines with extension props	1,315
Total number of lines with extension csproj	1,378
Number of lines of code with extension config	11
Number of lines of code with extension cs	124,216
Number of lines of code with extension props	1,315
Number of lines of code with extension csproj	1,378
Number of calls with call target	84,286
Number of calls with missing call target	1,691
Percentage of calls with call target	98.033
Number of compiler reported ambiguity errors	729
Number of compiler reported ambiguity error messages	310
Number of access with target	142,087
Number of expressions with known type	563,842
Number of expressions with unknown type	637
Number of type mentions with known type	116,315
Number of type mentions with unknown type	2,272
Is buildless extraction	1
Percentage of access with target	98.435
Percentage of expressions with known type	99.887
Percentage of type mentions with known type	98.084
Number of access with missing target	2,259

[hvitved]

LGTM. Should we also have something that counts UnknownExprs?

[tamasvajk]

LGTM. Should we also have something that counts UnknownExprs?

UnknownExpr is private. Should I count @unknown_expr directly?

[hvitved]

UnknownExpr is private. Should I count @unknown_expr directly?

Yes.

[michaelnebel]

@tamasvajk : This will be really helpful!!

[michaelnebel]

LGTM 👍