Split error string data across multiple lines.

Otherwise running git grep for a single function gives a ton of noise.

Change-Id: I18900d6269fd2be39ef9b579419aee1c7eca9143
Reviewed-on: https://boringssl-review.googlesource.com/3382
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/crypto/err/err_data_generate.go b/crypto/err/err_data_generate.go
index 003f7f4..ca20904 100644
--- a/crypto/err/err_data_generate.go
+++ b/crypto/err/err_data_generate.go
@@ -146,10 +146,10 @@
 	}
 	out.WriteString("};\n\n")
 
-	out.WriteString("static const char k" + name + "StringData[] = \"")
+	out.WriteString("static const char k" + name + "StringData[] =\n    \"")
 	for i, c := range st.stringData {
 		if c == 0 {
-			out.WriteString("\\0")
+			out.WriteString("\\0\"\n    \"")
 			continue
 		}
 		out.Write(st.stringData[i : i+1])