reinforce and explain that the page title must not contain resource references, including xref and image

resolves #1173 restore support for relative path token for include file in example or partial family

backport fix for #1170 coerce version value to string in refname projection; coerce null value to empty string

backport fix for #1176 populate breadcrumbs for orphan page when component version has no navigation

resolves #1177 log warning (instead of crashing) if Antora extension in playbook is missing require key

add docs on how to enable soft wrapping for source blocks

(cherry picked from commit 857c0781)

2bc683c7 add docs on how to enable soft wrapping for source blocks

Co-authored-by: Dan Allen <dan@opendevise.com>

backport fix for #1178 add require option to require method on GeneratorContext to use as fallback if module-scoped require fails

show full code for system git credential manager to make it easier to copy; show how to enable conditionally