Naming, layout and comments: descriptive full-word names, one item per line in wrapped calls and literals, and doc comments on exported names

Short and single-letter names in application code become full words (tests
keep theirs). Wrapped calls, signatures and composite literals put one item
per line, and one-line function bodies are expanded. Exported names and
groups of constants get doc comments, and comments refer to the renamed
identifiers.

internal/cli/config/config_test.go

@@ -63,8 +63,12 @@ func TestConfigShow(t *testing.T) {
 	cmdtest.Setup(t, appConfig)
 
 	out := mustRun(t, "config", "show")
-	cmdtest.Contains(t, out,
-		"logging.level = info <string>", "sources.sleeper.interval = 2m0s <string>")
+	cmdtest.Contains(
+		t,
+		out,
+		"logging.level = info <string>",
+		"sources.sleeper.interval = 2m0s <string>",
+	)
 	// Keys are listed in order, the same every time.
 	if again := mustRun(t, "config", "show"); again != out {
 		t.Errorf("config show output changed between runs:\n%s\n---\n%s", out, again)
@@ -158,8 +162,11 @@ func TestConfigSetUnset(t *testing.T) {
 		t.Errorf("config.yaml settings = %v; want %v", got, want)
 	}
 	// Back to the default.
-	cmdtest.Contains(t, mustRun(t, "config", "get", "sources.sleeper.interval"),
-		"10m0s <string>")
+	cmdtest.Contains(
+		t,
+		mustRun(t, "config", "get", "sources.sleeper.interval"),
+		"10m0s <string>",
+	)
 }
 
 func TestConfigSetWithoutConfigFile(t *testing.T) {