Polish pdb help messages and doc strings

[gaogaotiantian]

Feature or enhancement

Make pdb's help message less ugly.

Pitch

Currently, the help message of pdb is not pretty.

(Pdb) h a
a(rgs)
        Print the argument list of the current function.
(Pdb) 

a(rgs) is a little bit confusing by itself and the description's indentation is too long(directly from the docstring). commands is even worse.

(Pdb) h commands
commands [bpnumber]
        (com) ...
        (com) end
        (Pdb)

The docstring for each command is not entirely unified (whether there's a space between the command and the description) and for some docstrings they don't match the documentation.

(Pdb) h enable
enable bpnumber [bpnumber ...]

is different than the documentation enable [bpnumber ...]

We can make it better and more user friendly.

Linked PRs

• gh-103143: Polish pdb help messages and doc strings  #103144