Merge branch 'sn/doc-opt-notation' into maint

* sn/doc-opt-notation:
Fix {update,checkout}-index usage strings
Put a space between `<' and argument in pack-objects usage string
Remove stray quotes in --pretty and --format documentation
Use parentheses and `...' where appropriate
Fix odd markup in --diff-filter documentation
Use angles for placeholders consistently

diff --cc Documentation/git-show-branch.txt
Simple merge

diff --cc Documentation/git-update-index.txt
Simple merge

diff --cc Documentation/git.txt
Simple merge

diff --cc Documentation/user-manual.txt
Simple merge

diff --cc git-am.sh
Simple merge