Expand print context instead of climbing up the stack

[besfahbod]

At the moment, the dbg implementation walks up the stack to find a line with "dbg" in it:

pydbg/pydbg.py

Lines 27 to 29 in 4d787cd

	for i in reversed(inspect.stack()):
	ctx = i.code_context[0]
	if "dbg" in ctx:

Considering the fact that the expected use-case of this function is to put it literally in the code (and not pass around as a callback), I think it's safe to limit the stack lookup to only one level.

If we do that, we can then improve the context lookup to walk back on the line-of-code (to some maximum of like, 10) and print those out as the context for the call.

What do you think?

[tylerwince]

Are you thinking we do something like:

ctx = inspect.stack()[~1].code_context[0]
print(
    f"[{i.filename}:{i.lineno}] {ctx[ctx.find('(') + 1 : ctx.rfind(')')]} = {exp!r}"
)

so we don't have to iterate over the entire stack list to reverse it? You are likely right that we can only look up 1 level in the stack.