bookmarks: abort directly on invalid name This consolidates the abort message for a bookmark name containing invalid characters into one place, and renames the valid() method to checkvalid() to reflect the fact that it's no longer a predicate.

bookmarks: remove redundant check for newline New bookmarks are already checked for illegal characters (':', '\0', '\n', and '\r') in bookmarks.valid().

test-tag: test that all reserved names are rejected

amend: do a bare kill of temporary changeset Before this changeset the temporary changeset created by amend was made a precursors on the amend result. This add unnecessary complexity to the obsolescence graph. This temporary commit will probably disappear in the future. It is an unwanted byproduct of amend that nobody cares about.

amend: add noise in extra to avoid creating obsolescence cycle (issue3664) Obsolescence cycle are bad and should be avoided as much as possible. The current amend implemented touch changeset meta data as few as possible. This make is easy for amend to result in the same node than a precursors. We add some deterministic noise in extra to avoid this. In practice, the hex of the amended changeset is stored in 'amend_source' extra key.

changelog: extract description cleaning logic in a dedicated function The amend logic have use for it.

bookmarks: replace code-redundant comment with something more useful

bookmarks: remove another uneeded return

update: remove unnecessary argument check

grep: colorize all fields Colors were picked in accordance to GNU grep.

test-grep: add a test for -l

clfilter: remove use of xrange in revset For changelog level filtering to take effect it need to be used for any iteration. Some remaining use of `xrange` in revset code is replace by proper use of `changelog.revs` or direct iteration over changelog.