Count Consecutive Characters
Jelly, &nbsp;10 9 8 7&nbsp; 6 bytes

OṬṣ0ZL


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9 was using Sok's method: ṢQẆẇƇØaṪL

How?

OṬṣ0ZL - Link: list of (single-case) characters  e.g.  codegolf
O      - ordinal (vectorises)           [99,111,100,101,103,111,108,102]
 Ṭ     - untruth (1s at those indices)  [0,0,0,...,1,1,1,1,1,0,0,0,0,1,0,0,1]
       -                                 ^         ^       ^         ^     ^
       -                   i.e. indices: 1        99     103       108   111
   0   - literal zero
  ṣ    - split at                       [[],[],[],...,[1,1,1,1,1],[],[],[],[1],[],[1]]
    Z  - transpose                      [[1,1,1],[1],[1],[1],[1]]
     L - length                         5