Add more functions

[dmerejkowsky]

I often end up needed those in projects that depend on cli-ui, so might as well add them here.

First, h1, h2 and h3:

h1("Section")
h2("Sub section")
h2("Sub sub section")

Section
=======

Sub section
--------------

Sub sub section
+++++++++++++

• Then hr which would print an horizontal line taking all of the horizontal space

info("foo")
hr()

foo
-----------------------------------------------

I'm open to suggestions regarding naming (re-using HTML syntax may not be the best idea)

Also, maybe we need h3 to h6 ?

[greysign]

bro, coool library, nice job

[dmerejkowsky]

Other idea. Have a way to log multiple messages on the same line:

def erase_last_line() -> None:
    terminal_size = shutil.get_terminal_size()
    ui.info(" " * terminal_size.columns, end="\r")

ui.info("doing stuff", end="\n")
# ...
erase_last_line()

It's a pattern I've been using a few times