capability: fix "generated code" comment

According to [1], the generated files should contain a comment which
matches the following regexp:

	^// Code generated .* DO NOT EDIT\.$

Fix accordingly.

[1]: https://pkg.go.dev/cmd/go#hdr-Generate_Go_files_by_processing_source

Signed-off-by: Kir Kolyshkin <[email protected]>

Author: kolyshkin

capability/enum_gen.go

@@ -23,7 +23,7 @@ type generator struct {
 }
 
 func (g *generator) writeHeader() {
-	g.buf.WriteString("// generated file; DO NOT EDIT - use go generate in directory with source\n")
+	g.buf.WriteString("// Code generated by go generate; DO NOT EDIT.\n")
 	g.buf.WriteString("\n")
 	g.buf.WriteString("package capability")
 }