Tweaked dbg script headers to match the mount info log

The main difference being rendering the weight with a single letter "w"
prefix:

  $ ./scripts/dbglfs.py disk -b4096
  littlefs v0.0 4096x256 0x{1,0}.8b w2.512, rev eb7f2a0d
  ...

This lets us add valuable weight info without too much noise.

Adopting this in the dbg scripts is nice for consistency.

scripts/dbglfs.py

@@ -1884,11 +1884,13 @@ def main(disk, mroots=None, *,
         #### actual debugging begins here
 
         # print some information about the filesystem
-        print('littlefs v%s.%s %dx%d %s, rev %08x, weight %d.%d' % (
+        print('littlefs v%s.%s %dx%d %s w%d.%d, rev %08x' % (
             config.version[0] if config.version[0] is not None else '?',
             config.version[1] if config.version[1] is not None else '?',
             (config.geometry[0] or 0), (config.geometry[1] or 0),
-            mroot.addr(), mroot.rev, bweight//mleaf_weight, 1*mleaf_weight))
+            mroot.addr(),
+            bweight//mleaf_weight, 1*mleaf_weight,
+            mroot.rev))
 
         # dynamically size the id field
         w_width = max(