docs: Remove version markers

0.38 has a new API/ABI, so the Since: markers really aren't appropriate.

(cherry picked from commit 0a96716b8fe1a68d397862fc4dbb60dad5625c52)
widget: Check cursor's display before using it

(cherry picked from commit 19963440f9da89e2a3035c8a7488a92a244f22e3)