Efficiently replace targets in the buffer or context.
Substitute is a set of commands that perform text replacement (i)
throughout the buffer, (ii) limited to the current definition (per
narrow-to-defun), (iii) from point to the end of the buffer, and
(iv) from point to the beginning of the buffer.
These substitutions are meant to be as quick as possible and, as such,
differ from the standard
query-replace (which I still use). The
provided commands prompt for substitute text and perform the