[O] [fr] header-only versions of agenda faces like org-scheduled-today

[Samuel Wales]

tldr: add faces for the header parts of agenda faces so that variable
pitch can be used.

===

DISCUSSION:

in the agenda, it is desirable to use monospace fonts, so that things line up.

faces like org-scheduled-today affect the entire line.

however, monospace fonts are not needed for the text of a header.

there are 2 kinds of emacs users: those who are ok with monospace font
everywhere, and those who will never go back to monospace unless
something needs to line up.  :]

in addition to aesthetics and legibility, this is also useful for
putting more text on a line.

org provides for the second kind of emacs user by supplying separate
faces for timestamps and so on.  this works perfectly [except for a
few exceptions].  so you can set most things variable.

PROPOSAL:

it would excellent if we could have faces like
org-scheduled-today-header that would apply to the header text.
org-scheduled-today would apply to everything else on the line.  this
would allow variable pitch on the header text while keeping monospace
on category, leader, and so on.

for me this would allow much more text on the line.  currently i
cannot see the entire header for some headers.  [i use very large
fonts.  i already have the largest monitor i can use and use emacs
full screen and set the font size to the smallest legible size.  thus,
i have already done everything i can to increase text on the line.]

thanks!