Simplify tool pubspec setup (#4959)

We had a separate pubspec in the `/tool` directory, potentially causing
issues depending on where you ran `dart pub get` previously. This
simplifies to just using the pubspec in the root directory where you'll
run related commands.

Once this lands in your branch, you'll need to rerun `make setup`
to get the tool commands working.

Closes #4955

Author: parlough

pubspec.yaml

@@ -1,4 +1,5 @@
 name: site_www
+publish_to: none
 
 homepage: https://dart.dev
 
@@ -13,4 +14,5 @@ dev_dependencies:
     path: site-shared/packages/code_excerpter
   linkcheck: ^3.0.0
   lints: ^2.1.0
+  logging: ^1.2.0
   path: ^1.8.3

tool/check-links.sh

@@ -1,6 +1,6 @@
 #!/usr/bin/env bash
 # Check for non-200 links in built Jekyll site using Firebase emulator
-set -eu -o pipefail 
+set -eu -o pipefail
 source $TOOL_DIR/utils.sh
 
 dart pub get
@@ -33,7 +33,7 @@ sleep 3
 if [[ -z "$emulator_status" ]]; then
   echo -e "$(red "Emulator did not start...")"
   exit 1
-else 
+else
   echo -e "$(blue "Emulator is running")"
 fi