Add script editor `join_lines` keybind #82867

Job	Run time
📊 Static checks / Code style, file formatting, and docs	41s
🍎 macOS / Editor (target=editor)	5m 40s
🍎 macOS / Template (target=template_release)	2m 40s
🌐 Web / Template w/o threads (target=template_release, threads=no)	4m 20s
🐧 Linux / Editor with doubles and GCC sanitizers (target=editor, dev_build=yes, scu_build=yes, precision=double, use_asan=yes, use_ubsan=yes, linker=mold)	47m 20s
🏁 Windows / Template w/ GCC (target=template_release, use_mingw=yes)	4m 14s
🏁 Windows / Editor w/ clang-cl (target=editor, use_llvm=yes)	6m 7s
🏁 Windows / Template (target=template_release)	3m 3s
🤖 Android / Editor (target=editor)	6m 51s
🍏 iOS / Template (target=template_release)	1m 39s
🐧 Linux / Template w/ Mono, debug (target=template_debug)	2m 35s
🏁 Windows / Editor (target=editor)	10m 39s
🤖 Android / Template arm32 (target=template_debug, arch=arm32)	3m 2s
🐧 Linux / Editor with clang sanitizers (target=editor, dev_build=yes, use_asan=yes, use_ubsan=yes, use_llvm=yes, linker=lld)	9m 3s
🌐 Web / Template w/ threads (target=template_release, threads=yes)	4m 21s
🐧 Linux / Editor with ThreadSanitizer (target=editor, dev_build=yes, use_tsan=yes, use_llvm=yes, linker=lld)	7m 39s
🐧 Linux / Editor w/ Mono (target=editor)	20m 57s
🤖 Android / Template arm64 (target=template_debug, arch=arm64)	4m 29s
🐧 Linux / Template w/ Mono, release (target=template_release)	2m 52s
🐧 Linux / Minimal template (target=template_release, everything disabled)	2m 34s
	2h 30m 46s

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