https://reviews.llvm.org/D127702 adds the initial logpoints support in lldb-vscode. This patch further improves it by: 1. Adding a newline at the end of each log message 2. Support most of the format specifiers like \t, \n, \x etc.. The implementation is borrowed from FormatEntity::ParseInternal(). Future patch should merge these two implementations. Differential Revision: https://reviews.llvm.org/D136697