tests: make sed usage in test-unionrepo.t cross-platform Usage of the 'i' command proves tricky. I tried to write a check-code rule, but failed.

check-code: fix sed 'i' command rule newline matching The regular expression was meant to match cases where an 'i' command was not followed by precisely a '\' and then a newline; it failed to match the newline, so cases with a '\' but no newline would erroneously pass.

blackbox: don't run permission tests on non-unix systems The windows and vfat test runs were failing due to read/write permissions not working the same on those systems. On vfat, permissions can't be changed at all, and on windows it seems the chmod emulation doesn't remove read permissions. We could theoretically get the 'cannot write to blacklog.log' test to pass on windows but there's no #if condition to let us exclude vfat only. Verified that test-blackbox passes on windows now.

check-code: expand sed rule to include more offenders Expands the rule added in 5e4491c114b2 to include cases where the address is a line number instead of a regular expression, and fixes an instance of this pattern in test-unionrepo.t.

check-code: add a rule against a GNU sed-ism BSD sed requires the 'i' command to be followed with a backslash and a newline, like so: $ sed -e '/^@/i\ > other' We've encountered this problem before, e.g. in test-mq.t (900767dfa80d). This change adds a check-code rule and fixes two instances of the problem in test-record.t.

hgweb: make help verbose again (issue3899) Due to regression introduced in f5db3092790f, help in hgweb was rendered in non-verbose form (issue3899)

merge with i18n