Fix #646. Indentation of function arguments.

[Matafou]

Fix #646. Now indentation of function arguments are indented wrt to the function instead of aligned with the first argument. See details below.

Questions

• Is it too late for the including this in the soon to come V.4.5 tag? The indentation CI test are a good clue that this does not break indentation too much but we may wait for users to test this a bit.
• should we make the old behaviour still possible with a switch? I don't thinks coq-indent-box-style would be the right switch. I am not found of addig one more switch.

Details

This patch indents like this:

Definition foo :=
  myfunction (args1) arg2
    arg3.

instead of

Definition foo :=
  myfunction (args1) arg2
             arg3.

Besides when a function application is placed immediately after (and on the same line as) a "Com start" token, indentation is computed from the "Com start" instead. Because in practice the command start is the real function call. eg.:

Require Import
  Foo.

instead of

Require Import
        Foo.

A few tests have been added to check this new cases.
A few tests have been modified to reflect the change.

[Matafou]

also implements one of the feature wishes of #621 for indenting records ":=" asymmetrically.

[Matafou]

pushed a few more comments.