fix: update drifted file:line citations to match current golang/go source

Audited all file:line citations against golang/go HEAD.
97 citations checked; 9 had drifted by 1-20 lines (off-by-one or small
structural shifts in the stdlib source). Updated both inline code block
comments and corresponding GitHub #L anchor links.

Changes per file:
  patterns/api-conventions.md  - strings/builder.go WriteString (92→112), String (48→46)
  patterns/configuration.md    - crypto/tls/common.go Time field (572→575)
  patterns/documentation.md    - net/http/server.go Handler comment (64→65), os/file.go example (17→16)
  patterns/structs.md          - os/types.go File struct (16→15), strings/builder.go copyCheck (25→32)
  patterns/style.md            - net/http/server.go TLSConfig (3041→3040), import block (8→9)

patterns/api-conventions.md

@@ -247,14 +247,14 @@ type Builder struct {
     buf  []byte
 }
 
-// strings/builder.go:92-96
+// strings/builder.go:112-116
 func (b *Builder) WriteString(s string) (int, error) {
     b.copyCheck()
     b.buf = append(b.buf, s...)
     return len(s), nil
 }
 
-// strings/builder.go:48-50
+// strings/builder.go:46-48
 func (b *Builder) String() string {
     return unsafe.String(unsafe.SliceData(b.buf), len(b.buf))
 }