Add problem matcher for gettext --check messages

.github/gettext-problem-matcher.json

@@ -0,0 +1,16 @@
+{
+	"problemMatcher": [
+		{
+			"owner": "gettext",
+			"pattern": [
+				{
+					"regexp": "^(.+):(\\d+): (\\w+): (.+)$",
+					"file": 1,
+					"line": 2,
+					"severity": 3,
+					"message": 4
+				}
+			]
+		}
+	]
+}

.github/workflows/lint.yml

@@ -80,8 +80,10 @@ jobs:
       run: |
         sudo apt-get update
         sudo apt-get install gettext
+    - name: Add problem matcher
+      run: echo "::add-matcher::.github/gettext-problem-matcher.json"
     - name: Check locale files with gettext
-      run: make locale-check
+      run: make locale-check 2>&1 | sed -E 's#^([^ ]+\.po)#sphinx/locale/\1#'
 
   docs-lint:
     runs-on: ubuntu-latest