typo fix in command help text
This patch fixes a few typo errors on the command help output
(I am not sure if the change on 'diff' is the best though).
+ hg init
+ hg add a
+ hg commit -m commit #0 -d 0 0
+ hg add b
+ hg commit -m commit #1 -d 0 0
+ hg update 0
+ hg add c
+ hg commit -m commit #2 -d 0 0
+ hg update -m 1
+ hg init
+ hg add a
+ hg commit -m commit #0 -d 0 0
+ hg add b
+ hg commit -m commit #1 -d 0 0
+ hg update 0
+ hg add c
+ hg commit -m commit #2 -d 0 0
+ hg update -m 1
merging for b
merging b
+ hg init
+ hg add a
+ hg commit -m commit #0 -d 0 0
+ hg add b
+ hg commit -m commit #1 -d 0 0
+ hg commit -m commit #2 -d 0 0
+ hg update 1
+ hg add c
+ hg commit -m commit #3 -d 0 0
This is file b1
+ hg update -m 2
merging for b
merging b
+ hg init
+ hg add a
+ hg commit -m commit #0 -d 0 0
+ hg add b
+ hg commit -m commit #1 -d 0 0
+ hg commit -m commit #2 -d 0 0
+ hg update 1
+ hg add c
+ hg commit -m commit #3 -d 0 0
+ hg update -m 2
merging for b
merging b