Revert "Use ghcr.io for grammar compiler docker container" (#6546)

Revert "Use ghcr.io for grammar compiler docker container (#6322)"

This reverts commit fd7982704b.

script/grammar-compiler

@@ -3,7 +3,7 @@
 set -e
 cd "$(dirname "$0")/.."
 
-image="ghcr.io/github/linguist/grammar-compiler:latest"
+image="linguist/grammar-compiler:latest"
 mkdir -p grammars
 
 if [ -z "$REBUILD" ]; then

tools/grammars/docker/build

@@ -3,7 +3,7 @@
 set -e
 cd "$(dirname "$0")/.."
 
-image=ghcr.io/github/linguist/grammar-compiler
+image=linguist/grammar-compiler
 docker build -t $image .
 
 if [ "$1" = "--push" ]; then