This is similar to `\` at the line end in many languages like C and
allows you to split a very long string argument over several lines without
adding the EOL characters themselves.
The TECO equivalent to `\` would be ^Q, but it would be a semantic exception since
^Q (escaping) is supposed to _preserve_ the value of the following character.
Therefore I decided to use ^E instead.
This works with DOS and Mac line breaks as well.

If you have projects in different languages you can set different LSPs.
The default will still come from ~/.teco_ini if you decide to set one.
The default for $SCITECO_LSP_ROOT is set by session.tes' VCS integration
based on the VCS root, but you could still overwrite it per session.

* The main interface is the `FT` command.
  `FT` was an undocumented Video TECO command for etags/ctags lookups.
  I don't want to exactly copy its interface, though.
* `FT` allows looking up symbol names,
  definitions and references.
* ctags will be supported via ctags-lsp.
  LSP support is more powerful though and works without
  regenerating TAGS files all the time.
  The LSP will also allow you to customize auto-completions
  using SciTECO itself (i.e. by writing a language server
  in SciTECO).
* For multiple results, `FT$` can be used to cycle through
  results - this should mimic repeated `S$` or `N$`.
* `:FT...$` does a fuzzy search. IMHO it's not important
  to return a status integer instead. `FT` will only
  really be used in interactive mode.
* Document synchronization is supported via hooks from
  ring.c and via Scintilla notifications.
* Currently, the LSP communication is based on blocking
  GIOChannels. This means that a misbehaving hanging
  server could "lock up" the entire editor (FIXME).
  Only on ncurses you can always kill the subprocess by
  pressing CTRL+C.
  We need helper functions in spawn.c to read and write
  with interruptions.
* The textDocument/didChange notification transmits
  not only all edits, but all files' contents as well
  during initial synchronization.
  Therefore it is optimized to write and JSON-escape
  data without copying them around in memory and without
  destroying the buffer gap.
* Use $SCITECO_LSP to configure the language server.
  You can also use `tee` to capture stdin and stdout.
  Perhaps $SCITECO_LSP should be saved in .teco_session,
  so you can change it between projects?
* $SCITECO_LSP_ROOT is used to point to the project's
  root directory. session.tes will set it up automatically.

It will be useful for implementing LSP support.
It does not have JSON escape/unescape functions, so those
will still have to be written.

Source: https://github.com/rxi/sj.h

This is useful when writing small macros directly on the
command-line as in `sciteco --eval`. If you use double quoted shell
strings, too many characters have to be escaped.
If you use single-quotes, though, embedding the conditional end (')
is annoying -- it would have to be written as '\''.

Inlining the macro calls no longer results in a 25% speedup.

This for the first time mentions all of the bundled core libraries
in the end user documentation.

* Allows searching by regular expressions.
  We will never support all ARE constructs in TECO patterns, so this is useful to have available.
* Can only be typed upcaret.
  This leaves ^E~q available as an escape-regexp string building construct.
* Once we replace the pattern2regexp converter with a custom terex lexer,
  we might want to restrict ^~ to the beginning of the pattern.
  Currently, however it can be anywhere, so you can mix TECO patterns with regular expressions.

* The terminal's default foreground and background colors
  are now used by default (`sciteco --no-profile`), so SciTECO
  integrates naturally into all terminal color schemes, even
  dark-on-bright ones.
* The default Scintilla colors use only 0x000000 (COLOR_BLACK) and 0xC0C0C0 (COLOR_WHITE)
  now.
* You can use `7EJ` to configure the default colors in color
  schemes or your profile.
  All existing color schemes had to disable default colors
  (`-1,-1,7EJ`) since they wouldn't look well otherwise.
* You may add `-1,7EJ` to ~/.teco_ini when using a terminal emulator
  with a washed-out palettized COLOR_BLACK.
  We cannot detect the terminal's default colors automatically.
* Scinterm updated to v6.0.
  We require a not-yet-upstreamed patch:
  https://github.com/orbitalquark/scinterm/pull/40
* In fact, we might decide not to support default colors at all in Scinterm,
  so this feature should be considered experimental.