api/types: add missing GoDoc for BuildCache fields.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

api/types/types.go

@@ -772,18 +772,27 @@ type BuildResult struct {
 	ID string
 }
 
-// BuildCache contains information about a build cache record
+// BuildCache contains information about a build cache record.
 type BuildCache struct {
-	ID          string
-	Parent      string
-	Type        string
+	// ID is the unique ID of the build cache record.
+	ID string
+	// Parent is the ID of the parent build cache record.
+	Parent string
+	// Type is the cache record type.
+	Type string
+	// Description is a description of the build-step that produced the build cache.
 	Description string
-	InUse       bool
-	Shared      bool
-	Size        int64
-	CreatedAt   time.Time
-	LastUsedAt  *time.Time
-	UsageCount  int
+	// InUse indicates if the build cache is in use.
+	InUse bool
+	// Shared indicates if the build cache is shared.
+	Shared bool
+	// Size is the amount of disk space used by the build cache (in bytes).
+	Size int64
+	// CreatedAt is the date and time at which the build cache was created.
+	CreatedAt time.Time
+	// LastUsedAt is the date and time at which the build cache was last used.
+	LastUsedAt *time.Time
+	UsageCount int
 }
 
 // BuildCachePruneOptions hold parameters to prune the build cache