Workaround for Chroma detecting line feed as error

Glamour renders \n as visible error when rendering VimL code blocks.
This is due to lexer bug in Chroma, now fixed, but yet to be released,
combined with the code block error style in Glamour rendering errors
with a red background (rather than Chroma default of using red text).

See alecthomas/chroma#827 for more info

Updating Glamour styles to use red text rather than a red background
works around this, because there is no printable text to highlight.

Note that for dracula, the style for generic deleted and error are now
the same, but this seems a reasonable compromise as generic deleted is
primarily for diffs, which seem less likely to result in lexer errors.

Although this might seem like a fugly hack to address one specific
issue, it seems a pretty reasonable default to me as Glamour has no
control over Chroma's parsing of code blocks, only the highlighting,
and barring a new release of Glamour with updated dependencies, cannot
do anything about Chroma lexer errors other than highlight them.

styles/dark.json

@@ -96,8 +96,7 @@
         "color": "#C4C4C4"
       },
       "error": {
-        "color": "#F1F1F1",
-        "background_color": "#F05B5B"
+        "color": "#F05B5B"
       },
       "comment": {
         "color": "#676767"

styles/dracula.json

@@ -91,8 +91,7 @@
         "color": "#f8f8f2"
       },
       "error": {
-        "color": "#f8f8f2",
-        "background_color": "#ff5555"
+        "color": "#ff5555"
       },
       "comment": {
         "color": "#6272A4"

styles/light.json

@@ -95,8 +95,7 @@
         "color": "#2A2A2A"
       },
       "error": {
-        "color": "#F1F1F1",
-        "background_color": "#FF5555"
+        "color": "#FF5555"
       },
       "comment": {
         "color": "#8D8D8D"