Rewrite the gtksourceview highlighting file to make better use
of available syntax options. This allows us to separate various
contexts, and means we don't have to keep track of all conky
keywords.
Overview of changes:
* Use separate contexts for config block and "lit string".
* (lit string is the lua lit string [[ .. ]], we assume that
this is used to contain text sections or template blocks)
* Use "sub-string" highlighting to highlight parts of identifiers
separately.
* Added conky.text comments (from '#' to EOL).
* Remove lists of keywords and instead rely on syntax implications.
* Uses separate contexts for config 'key=val' and text '${var}'s.
* Match escape sequences more precisely.
* Lua and conky escape sequences matched separately; lua in normal
strings and conky in literal strings. See escapes note.
* Transition from camelCase to hyphen-separated names
* Reword README to reflect changes
Escapes note:
We also match conky template escape sequences when in lua literal
strings as it would be too messy to separate `conky.text` and
`templateN = ` literal strings.
We currently don't match time format escape sequences as this would
require knowing which text variable we are in. This is only possible
if we duplicate the `bracket-var` context (less painful than
duplicating the `lua-literal-string` context).
Signed-off-by: Matt Sturgeon <matt@sturgeon.me.uk>
