* Since regular editors' font sizes and families are controlled by
  the settings and not the theme, don't store a dummy text style in
  the theme. Instead, only store a font color, and synthesize
  the text style for regular editors using both the theme and the
  settings.
* Style single-line and auto-height editors (now called "field
  editors") using a single function that takes the entire theme and
  selects a relevant sub-object.

Co-Authored-By: Nathan Sobo <nathan@zed.dev>