Minor improvement to documentation over block_cycles

Suggested by haneefmubarak

lfs.c

@@ -3192,11 +3192,15 @@ static int lfs_init(lfs_t *lfs, const struct lfs_config *cfg) {
     LFS_ASSERT(4*lfs_npw2(0xffffffff / (lfs->cfg->block_size-2*4))
             <= lfs->cfg->block_size);
 
-    // block_cycles = 0 is no longer supported, must either set a number
-    // of erase cycles before moving logs to another block (~500 suggested),
-    // or explicitly disable wear-leveling with -1.
+    // block_cycles = 0 is no longer supported.
+    //
+    // block_cycles is the number of erase cycles before littlefs evicts
+    // metadata logs as a part of wear leveling. Suggested values are in the
+    // range of 100-1000, or set block_cycles to -1 to disable block-level
+    // wear-leveling.
     LFS_ASSERT(lfs->cfg->block_cycles != 0);
 
+
     // setup read cache
     if (lfs->cfg->read_buffer) {
         lfs->rcache.buffer = lfs->cfg->read_buffer;

lfs.h

@@ -190,9 +190,10 @@ struct lfs_config {
     // Number of erasable blocks on the device.
     lfs_size_t block_count;
 
-    // Number of erase cycles before we should move logs to another block.
-    // Suggested values are in the range 100-1000, with large values having
-    // better performance at the cost of less consistent wear distribution.
+    // Number of erase cycles before littlefs evicts metadata logs and moves 
+    // the metadata to another block. Suggested values are in the
+    // range 100-1000, with large values having better performance at the cost
+    // of less consistent wear distribution.
     //
     // Set to -1 to disable block-level wear-leveling.
     int32_t block_cycles;