scripts/*.py: update coding style (#10761)

* convert to f string

* use a next function instead of a for-loop

* remove uneeded else statement

* use in operator instead of multi comparison

* conver to f string

* adds extra line between function defs

* revert/change to PR comment around looping

* remove uneeded loops

* revert to keep old style choice

scripts/pdf/render.py

@@ -26,7 +26,7 @@ def main(loc, colorscheme):
     # Set up css style sheets
     csslist = ["basic.css"]
     if colorscheme != "basic":
-        csslist.append(colorscheme + ".css")
+        csslist.append(f"{colorscheme}.css")
 
     # A string that stores all pages in HTML format
     html = (