Variable: font-lock-support-mode

Support mode for Font Lock mode.
Support modes speed up Font Lock mode by being choosy about when fontification
occurs. The default support mode, Just-in-time Lock mode (symbol
`jit-lock-mode'), is recommended.

Other, older support modes are Fast Lock mode (symbol `fast-lock-mode') and
Lazy Lock mode (symbol `lazy-lock-mode'). See those modes for more info.
However, they are no longer recommended, as Just-in-time Lock mode is better.

If nil, means support for Font Lock mode is never performed.
If a symbol, use that support mode.
If a list, each element should be of the form (MAJOR-MODE . SUPPORT-MODE),
where MAJOR-MODE is a symbol or t (meaning the default). For example:
((c-mode . fast-lock-mode) (c++-mode . fast-lock-mode) (t . lazy-lock-mode))
means that Fast Lock mode is used to support Font Lock mode for buffers in C or
C++ modes, and Lazy Lock mode is used to support Font Lock mode otherwise.

The value of this variable is used when Font Lock mode is turned on.