force the use of the en_US dictionary (#6863)
force the use of the en_US dictionary (#6863)

check_spelling_pedantic uses aspell, which uses the system dictionary
unless told otherwise. Envoy's codebase has settled on using en_US as
its dictionary, so we should force aspell to use it as well.

Signed-off-by: Kyle Larose <3c25b01657254677d3e1a8fd1f0742c5d489bd39@agilicus.com>
lizan/envoy,envoyproxy/envoy-wasm,istio/envoy,envoyproxy/envoy,lyft/envoy,envoyproxy/envoy,istio/envoy,istio/envoy,envoyproxy/envoy,envoyproxy/envoy,envoyproxy/envoy,lyft/envoy,jrajahalme/envoy,envoyproxy/envoy-wasm,lizan/envoy,istio/envoy,jrajahalme/envoy,envoyproxy/envoy,eklitzke/envoy,jrajahalme/envoy,lizan/envoy,envoyproxy/envoy-wasm,lyft/envoy,envoyproxy/envoy-wasm,eklitzke/envoy,envoyproxy/envoy,lyft/envoy,lyft/envoy,lizan/envoy,envoyproxy/envoy-wasm,jrajahalme/envoy,envoyproxy/envoy,jrajahalme/envoy,istio/envoy,lizan/envoy,envoyproxy/envoy,eklitzke/envoy,istio/envoy,eklitzke/envoy,envoyproxy/envoy,envoyproxy/envoy-wasm,lizan/envoy,eklitzke/envoy,lyft/envoy,jrajahalme/envoy,istio/envoy,envoyproxy/envoy,envoyproxy/envoy-wasm,envoyproxy/envoy,eklitzke/envoy