rebase: while rewriting desc hashes, ignore ambiguous prefix "hashes"
If a repo is sufficiently large, a six digit number "hash prefix" can somewhat
easily reference an ambiguous hash prefix.
Differential Revision: https://phab.mercurial-scm.org/D12552
help: set the large-file-limit to 10MB
This is a minor increase (5%) and makes the doc much clearer.
Differential Revision: https://phab.mercurial-scm.org/D12484