Add tests for writer.go

Author: mcy

.gitignore

@@ -0,0 +1,3 @@
+# The output of go build ./cmd/protoscope
+protoscope
+

README.md

@@ -25,6 +25,7 @@ dissassembling with `protoscope`, making edits, and then reassembling with
 They may also be used to inspect proto files (or things that look like them.)
 
 For the language specification and basic examples, see [language.txt](/language.txt).
+Example disassembly can be found under [./testdata](/testdata).
 
 ## Backwards compatibility
 

scanner_test.go

@@ -543,7 +543,7 @@ func TestScan(t *testing.T) {
 				0x80, 0x01,
 				0x46,
 
-				0x08, 55 * 2,
+				0x08, 55*2,
 				0x11, num2le(1.23),
 				0x1a, 0x04, "text",
 				0x35, 0xff, 0xff, 0xff, 0xff,