Fix wrong/outdated color config references

Author: Kissaki

book/coloring_and_theming.md

@@ -327,7 +327,7 @@ Here's a small example of changing some of these values.
 $env.config.color_config.separator = purple
 $env.config.color_config.leading_trailing_space_bg = "#ffffff"
 $env.config.color_config.header = gb
-$env.config.color_config.date = wd
+$env.config.color_config.datetime = wd
 $env.config.color_config.filesize = c
 $env.config.color_config.row_index = cb
 $env.config.color_config.bool = red
@@ -338,7 +338,7 @@ $env.config.color_config.float = red
 $env.config.color_config.string = white
 $env.config.color_config.nothing = red
 $env.config.color_config.binary = red
-$env.config.color_config.cellpath = cyan
+$env.config.color_config.cell-path = cyan
 $env.config.color_config.hints = dark_gray
 ```
 
@@ -352,7 +352,7 @@ $env.config.color_config.header = { # this is like PR #489
     bg: "#ffb900", # note, commas are not required, it could also be all on one line
     attr: bli # note, there are no quotes around this value. it works with or without quotes
 }
-$env.config.color_config.date = "#75507B"
+$env.config.color_config.datetime = "#75507B"
 $env.config.color_config.filesize = "#729fcf"
 $env.config.color_config.row_index = {
     # note, that this is another way to set only the foreground, no need to specify bg and attr