Add a few more Go-related commands

src/golang.md

@@ -28,6 +28,9 @@ go version
 
 # Find where the current module would be installed to.
 go list -f '{{.Target}}'
+
+# List environment information, including where packages are installed via go get.
+go env
 ```
 
 ## Requirements
@@ -37,6 +40,9 @@ go mod edit -replace example.com/greetings=../greetings
 
 # Get an external module and add to go.mod require.
 go get golang.org/x/example
+
+# Get dependencies for code in the current directory (already added as an import).
+go get .
 ```
 
 ## Workspaces