Sort operations to guarantee a stable order (Khan#156)

Problem: currently when using a wildcard that covers multiple files in `operations:` YAML directive the generator emits functions in a non-stable ordering due to the use of map for storing file names:

https://github.com/Khan/genqlient/blob/e0accbded177db9143314911bacedf61b2cda656/generate/parse.go#L68-L84

Solution: sort the operations before emitting them.

generate/generate.go

@@ -341,6 +341,12 @@ func Generate(config *Config) (map[string][]byte, error) {
 	if err != nil {
 		return nil, err
 	}
+
+	// Sort operations to guarantee a stable order
+	sort.Slice(g.Operations, func(i, j int) bool {
+		return g.Operations[i].Name < g.Operations[j].Name
+	})
+
 	for _, operation := range g.Operations {
 		err = g.render("operation.go.tmpl", &bodyBuf, operation)
 		if err != nil {

go.sum

@@ -14,7 +14,6 @@ github.com/arbovm/levenshtein v0.0.0-20160628152529-48b4e1c0c4d0 h1:jfIu9sQUG6Ig
 github.com/arbovm/levenshtein v0.0.0-20160628152529-48b4e1c0c4d0/go.mod h1:t2tdKJDJF9BV14lnkjHmOQgcvEKgtqs5a1N3LNdJhGE=
 github.com/bradleyjkemp/cupaloy/v2 v2.6.0 h1:knToPYa2xtfg42U3I6punFEjaGFKWQRXJwj0JTv4mTs=
 github.com/bradleyjkemp/cupaloy/v2 v2.6.0/go.mod h1:bm7JXdkRd4BHJk9HpwqAI8BoAY1lps46Enkdqw6aRX0=
-github.com/cpuguy83/go-md2man/v2 v2.0.0-20190314233015-f79a8a8ca69d h1:U+s90UTSYgptZMwQh2aRr3LuazLJIa+Pg3Kc1ylSYVY=
 github.com/cpuguy83/go-md2man/v2 v2.0.0-20190314233015-f79a8a8ca69d/go.mod h1:maD7wRr/U5Z6m/iR4s+kqSMx2CaBsrgA7czyZG/E6dU=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
@@ -36,7 +35,6 @@ github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
 github.com/kr/text v0.1.0 h1:45sCR5RtlFHMR4UwH9sdQ5TC8v0qDQCHnXt+kaKSTVE=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
 github.com/logrusorgru/aurora v0.0.0-20200102142835-e9ef32dff381/go.mod h1:7rIyQOR62GCctdiQpZ/zOJlFyk6y+94wXzv6RNZgaR4=
-github.com/matryer/moq v0.0.0-20200106131100-75d0ddfc0007 h1:reVOUXwnhsYv/8UqjvhrMOu5CNT9UapHFLbQ2JcXsmg=
 github.com/matryer/moq v0.0.0-20200106131100-75d0ddfc0007/go.mod h1:9ELz6aaclSIGnZBoaSLZ3NAl1VTufbOrXBPvtcy6WiQ=
 github.com/mattn/go-colorable v0.1.4/go.mod h1:U0ppj6V5qS13XJ6of8GYAs25YV2eR4EVcfRqFIhoBtE=
 github.com/mattn/go-isatty v0.0.8/go.mod h1:Iq45c/XA43vh69/j3iqttzPXn0bhXyGjM0Hdxcsrc5s=
@@ -45,17 +43,14 @@ github.com/mitchellh/mapstructure v0.0.0-20180203102830-a4e142e9c047 h1:zCoDWFD5
 github.com/mitchellh/mapstructure v0.0.0-20180203102830-a4e142e9c047/go.mod h1:FVVH3fgwuzCH5S8UJGiWEs2h04kUh9fWfEaFds41c1Y=
 github.com/opentracing/basictracer-go v1.0.0/go.mod h1:QfBfYuafItcjQuMwinw9GhYKwFXS9KnPs5lxoYwgW74=
 github.com/opentracing/opentracing-go v1.0.2/go.mod h1:UkNAQd3GIcIGf0SeVgPpRdFStlNbqXla1AfSYxPUl2o=
-github.com/pkg/errors v0.8.1 h1:iURUrRGxPUNPdy5/HRSm+Yj6okJ6UtLINN0Q9M4+h3I=
 github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/rs/cors v1.6.0/go.mod h1:gFx+x8UowdsKA9AchylcLynDq+nNFfI8FkUZdN/jGCU=
-github.com/russross/blackfriday/v2 v2.0.1 h1:lPqVAte+HuHNfhJ/0LC98ESWRz8afy9tM/0RK8m9o+Q=
 github.com/russross/blackfriday/v2 v2.0.1/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
 github.com/sergi/go-diff v1.1.0 h1:we8PVUC3FE2uYfodKH/nBHMSetSfHDR6scGdBi+erh0=
 github.com/sergi/go-diff v1.1.0/go.mod h1:STckp+ISIX8hZLjrqAeVduY0gWCT9IjLuqbuNXdaHfM=
 github.com/shurcooL/httpfs v0.0.0-20171119174359-809beceb2371/go.mod h1:ZY1cvUeJuFPAdZ/B6v7RHavJWZn2YPVFQ1OSXhCGOkg=
-github.com/shurcooL/sanitized_anchor_name v1.0.0 h1:PdmoCO6wvbs+7yrJyMORt4/BmY5IYyJwS/kOiWx8mHo=
 github.com/shurcooL/sanitized_anchor_name v1.0.0/go.mod h1:1NzhyTcUVG4SuEtjjoZeVRXNmyL/1OwPU0+IJeTBvfc=
 github.com/shurcooL/vfsgen v0.0.0-20180121065927-ffb13db8def0/go.mod h1:TrYk7fJVaAttu97ZZKrO9UbRa8izdowaMIZcxYMbVaw=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
@@ -66,9 +61,7 @@ github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81P
 github.com/stretchr/testify v1.6.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
 github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
-github.com/urfave/cli/v2 v2.1.1 h1:Qt8FeAtxE/vfdrLmR3rxR6JRE0RoVmbXu8+6kZtYU4k=
 github.com/urfave/cli/v2 v2.1.1/go.mod h1:SE9GqnLQmjVa0iPEY0f1w3ygNIYcIJ0OKPMoW2caLfQ=
-github.com/vektah/dataloaden v0.2.1-0.20190515034641-a19b9a6e7c9e h1:+w0Zm/9gaWpEAyDlU1eKOuk5twTjAjuevXqcJJw8hrg=
 github.com/vektah/dataloaden v0.2.1-0.20190515034641-a19b9a6e7c9e/go.mod h1:/HUdMve7rvxZma+2ZELQeNh88+003LL7Pf/CZ089j8U=
 github.com/vektah/gqlparser/v2 v2.2.0 h1:bAc3slekAAJW6sZTi07aGq0OrfaCjj4jxARAaC7g2EM=
 github.com/vektah/gqlparser/v2 v2.2.0/go.mod h1:i3mQIGIrbK2PD1RrCeMTlVbkF2FJ6WkU1KJlJlC+3F4=