multi: Fix typos [skip ci]

mobile/README.md

@@ -223,7 +223,7 @@ If Android Studio tells you that the `aar` file cannot be included into the `app
 
 ![separate_gradle_module](docs/separate_gradle_module.png)
 
-3. Gradle file should countain only these lines:
+3. Gradle file should contain only these lines:
 
 ```shell
 configurations.maybeCreate("default")

mobile/bindings.go

@@ -16,7 +16,7 @@ import (
 	"google.golang.org/grpc"
 )
 
-// lndStarted will be used atomically to ensure only a singel lnd instance is
+// lndStarted will be used atomically to ensure only a single lnd instance is
 // attempted to be started at once.
 var lndStarted int32