Internal: Added ImGuiInputTextState::ClearText() helper.
Internal: Added ImGuiInputTextState::ClearText() helper.

bkaradzic/imgui,ocornut/imgui,dougbinks/imgui,Flix01/imgui,cmaughan/imgui,ggtucker/imgui,cmaughan/imgui,Flix01/imgui,dougbinks/imgui,nProtect/imgui,bkaradzic/imgui,cmaughan/imgui,ggtucker/imgui,burningreggae/imgui,burningreggae/imgui,ggtucker/imgui,ocornut/imgui,nProtect/imgui,aimotive/imgui-glfw,nProtect/imgui,cmaughan/imgui,bkaradzic/imgui,aimotive/imgui-glfw,Flix01/imgui,ocornut/imgui