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/mock/findatender/ratelimit.go

@@ -50,46 +50,50 @@ func (rl *RateLimiter) allow(key string) (bool, int) {
 	now := rl.now().UTC()
 	hour := now.Truncate(time.Hour)
 
-	c, ok := rl.clients[key]
-	if !ok || !c.hour.Equal(hour) {
+	client, ok := rl.clients[key]
+	if !ok || !client.hour.Equal(hour) {
 		// First request of this clock hour: it anchors the windows.
 		if !ok && len(rl.clients) > 10000 {
 			rl.prune(hour)
 		}
-		c = &clientWindow{hour: hour, anchor: now, windowStart: now}
-		rl.clients[key] = c
+		client = &clientWindow{
+			hour:        hour,
+			anchor:      now,
+			windowStart: now,
+		}
+		rl.clients[key] = client
 	}
 
 	// Move to whichever fixed window, counted from the anchor, now falls in.
-	idx := now.Sub(c.anchor) / rl.window
-	if ws := c.anchor.Add(idx * rl.window); !ws.Equal(c.windowStart) {
-		c.windowStart = ws
-		c.count = 0
+	index := now.Sub(client.anchor) / rl.window
+	if windowStart := client.anchor.Add(index * rl.window); !windowStart.Equal(client.windowStart) {
+		client.windowStart = windowStart
+		client.count = 0
 	}
 
-	if c.count < rl.limit {
-		c.count++
+	if client.count < rl.limit {
+		client.count++
 		return true, 0
 	}
 
 	// The next window opens at the end of this one, or at the top of the
 	// next hour if that comes first (because a new hour re-anchors).
-	next := c.windowStart.Add(rl.window)
-	if nh := hour.Add(time.Hour); nh.Before(next) {
-		next = nh
+	next := client.windowStart.Add(rl.window)
+	if nextHour := hour.Add(time.Hour); nextHour.Before(next) {
+		next = nextHour
 	}
-	secs := int((next.Sub(now) + time.Second - 1) / time.Second) // round up
-	if secs < 1 {
-		secs = 1
+	seconds := int((next.Sub(now) + time.Second - 1) / time.Second) // round up
+	if seconds < 1 {
+		seconds = 1
 	}
-	return false, secs
+	return false, seconds
 }
 
 // prune drops clients whose state belongs to an earlier hour.
 func (rl *RateLimiter) prune(hour time.Time) {
-	for k, c := range rl.clients {
-		if c.hour.Before(hour) {
-			delete(rl.clients, k)
+	for key, client := range rl.clients {
+		if client.hour.Before(hour) {
+			delete(rl.clients, key)
 		}
 	}
 }