Rust: Add % of files extractor without errors to summary stats.

Author: geoffw0

rust/ql/src/queries/summary/SummaryStats.ql

@@ -32,6 +32,11 @@ where
   key = "Files extracted - without errors" and
   value = count(SuccessfullyExtractedFile f | exists(f.getRelativePath()))
   or
+  key = "Files extracted - without errors %" and
+  value =
+    (count(SuccessfullyExtractedFile f | exists(f.getRelativePath())) * 100) /
+      count(ExtractedFile f | exists(f.getRelativePath()))
+  or
   key = "Lines of code extracted" and value = getLinesOfCode()
   or
   key = "Lines of user code extracted" and value = getLinesOfUserCode()

rust/ql/test/query-tests/diagnostics/SummaryStats.expected

@@ -5,6 +5,7 @@
 | Files extracted - total | 7 |
 | Files extracted - with errors | 3 |
 | Files extracted - without errors | 4 |
+| Files extracted - without errors % | 57 |
 | Inconsistencies - AST | 0 |
 | Inconsistencies - CFG | 0 |
 | Inconsistencies - data flow | 0 |