add some comments

Author: andrewmbenton

internal/cmd/shim.go

@@ -53,16 +53,16 @@ func pluginOverride(r *compiler.Result, o config.Override) *plugin.Override {
 }
 
 func pluginSettings(r *compiler.Result, cs config.CombinedSettings) *plugin.Settings {
-	var overrides []*plugin.Override
+	var over []*plugin.Override
 	for _, o := range cs.Overrides {
-		overrides = append(overrides, pluginOverride(r, o))
+		over = append(over, pluginOverride(r, o))
 	}
 	return &plugin.Settings{
 		Version:   cs.Global.Version,
 		Engine:    string(cs.Package.Engine),
 		Schema:    []string(cs.Package.Schema),
 		Queries:   []string(cs.Package.Queries),
-		Overrides: overrides,
+		Overrides: over,
 		Rename:    cs.Rename,
 		Codegen:   pluginCodegen(cs, cs.Codegen),
 	}

internal/codegen/golang/opts/go_type.go

@@ -1,3 +1,4 @@
+// Copied from github.com/sqlc-dev/sqlc/internal/config/go_type.go with minor changes to ParsedGoType
 package opts
 
 import (

internal/codegen/golang/opts/override.go

@@ -1,3 +1,4 @@
+// Copied from github.com/sqlc-dev/sqlc/internal/config/override.go and removed Engine field from Override
 package opts
 
 import (

internal/codegen/golang/opts/plugin_override.go

@@ -1,3 +1,4 @@
+// Extracted from github.com/sqlc-dev/sqlc/internal/cmd/shim.go
 package opts
 
 import (