fix(#185): remove synchronization in XSLDocument

See #269, release log:

• 48854d6 by @yegor256: java9 fix
• e0c60c0 by @rultor: Merge branch '__rultor'
• edb9409 by @yegor256: java9 fix
• 34c9970 by @maxonfjvipon: fix(#185): back
• b0e73ed by @maxonfjvipon: fix(#185): space
• 98bd176 by @yegor256: typos
• 129c7d3 by @yegor256: license
• c371244 by @yegor256: badge
• 84bbdca by @yegor256: year up
• 2ed2d07 by @maxonfjvipon: fix(#185): qulice
• cc57a35 by @yegor256: md fix
• 4070260 by @yegor256: Merge pull request #237 from j...
• ed34caf by @yegor256: yamls
• 8487bc5 by @maxonfjvipon: fix(#185): message back
• 6c093bc by @maxonfjvipon: fix(#185): remove synchronizat...
• df340cf by @renovate[bot]: fix(deps): update dependency o...
• 65f148b by @renovate[bot]: chore(deps): update junit5 mon...
• f57ef84 by @renovate[bot]: fix(deps): update dependency o...
• 2aa2722 by @renovate[bot]: chore(deps): update junit5 mon...
• e20ea4a by @renovate[bot]: chore(deps): update dependency...
• and 58 more...

Released by Rultor 2.0-SNAPSHOT, see build log