x/vulndb: replace internal.Cut with strings.Cut

Remove function internal.Cut and replace with strings.Cut which was introduced in Go 1.18.

Fixes golang/go#52571

Change-Id: I0fa926cfc7cd7ecf69ab1ebbc0c852dc22741a12
Reviewed-on: https://go-review.googlesource.com/c/vulndb/+/402414
Run-TryBot: Tatiana Bradley <tatiana@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Jonathan Amsterdam <jba@google.com>
Reviewed-by: Tatiana Bradley <tatiana@golang.org>

internal/internal.go

@@ -37,18 +37,3 @@ func ReadFileLines(filename string) (lines []string, err error) {
 	}
 	return lines, nil
 }
-
-// Cut cuts s around the first instance of sep,
-// returning the text before and after sep.
-// The found result reports whether sep appears in s.
-// If sep does not appear in s, cut returns s, "", false.
-//
-// https://golang.org/issue/46336 is an accepted proposal to add this to the
-// standard library. It will presumably land in Go 1.18, so this can be removed
-// when pkgsite moves to that version.
-func Cut(s, sep string) (before, after string, found bool) {
-	if i := strings.Index(s, sep); i >= 0 {
-		return s[:i], s[i+len(sep):], true
-	}
-	return s, "", false
-}

internal/report/ghsa.go

@@ -8,7 +8,6 @@ import (
 	"fmt"
 	"strings"
 
-	"golang.org/x/vulndb/internal"
 	"golang.org/x/vulndb/internal/ghsa"
 )
 
@@ -112,7 +111,7 @@ func parseVulnRange(s string) ([]vulnRangeItem, error) {
 		if p == "" {
 			continue
 		}
-		before, after, found := internal.Cut(p, " ")
+		before, after, found := strings.Cut(p, " ")
 		if !found {
 			return nil, fmt.Errorf("invalid vuln range item %q", p)
 		}