go/analysis/internal/checker: correct comment grammar

Change-Id: I78b41326c5d8d22fbff40f89721ac3aad3a5c63c
Reviewed-on: https://go-review.googlesource.com/c/158841
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
diff --git a/go/analysis/internal/checker/checker.go b/go/analysis/internal/checker/checker.go
index 0d36e0b..6422e8d 100644
--- a/go/analysis/internal/checker/checker.go
+++ b/go/analysis/internal/checker/checker.go
@@ -42,7 +42,7 @@
 	CPUProfile, MemProfile, Trace string
 )
 
-// RegisterFlags registers command-line flags used the analysis driver.
+// RegisterFlags registers command-line flags used by the analysis driver.
 func RegisterFlags() {
 	// When adding flags here, remember to update
 	// the list of suppressed flags in analysisflags.