docs(autocompletion): update autocompletion docs

Update the autocompletion documentation (in `README` and `man` page) to
include information about configuring `zsh` autocompletion script.

doc/cheat.1

@@ -175,15 +175,17 @@ For detailed instructions on how to configure cheatpaths, please refer
 to the comments in conf.yml.
 .SS Autocompletion
 .PP
-Autocompletion scripts for \f[B]bash\f[]/\f[B]zsh\f[] and \f[B]fish\f[]
-are available for download:
+Autocompletion scripts for \f[B]bash\f[], \f[B]zsh\f[], and
+\f[B]fish\f[] are available for download:
 .IP \[bu] 2
 <https://github.com/cheat/cheat/blob/master/scripts/cheat.bash>
 .IP \[bu] 2
 <https://github.com/cheat/cheat/blob/master/scripts/cheat.fish>
+.IP \[bu] 2
+<https://github.com/cheat/cheat/blob/master/scripts/cheat.zsh>
 .PP
-The \f[B]bash\f[]/\f[B]zsh\f[] scripts provide optional integration with
-\f[B]fzf\f[], if the latter is available on your \f[B]PATH\f[].
+The \f[B]bash\f[] and \f[B]zsh\f[] scripts provide optional integration
+with \f[B]fzf\f[], if the latter is available on your \f[B]PATH\f[].
 .PP
 The installation process will vary per system and shell configuration,
 and thus will not be discussed here.
@@ -195,6 +197,12 @@ If \f[B]CHEAT_CONFIG_PATH\f[] is set, all other config paths will be
 ignored.
 .RS
 .RE
+.TP
+.B \f[B]CHEAT_USE_FZF\f[]
+If set, autocompletion scripts will attempt to integrate with
+\f[B]fzf\f[].
+.RS
+.RE
 .SH BUGS
 .PP
 See GitHub issues: <https://github.com/cheat/cheat/issues>

doc/cheat.1.md

@@ -137,14 +137,15 @@ comments in conf.yml.
 
 Autocompletion
 --------------
-Autocompletion scripts for **bash**/**zsh** and **fish** are available for
+Autocompletion scripts for **bash**, **zsh**, and **fish** are available for
 download:
 
 - <https://github.com/cheat/cheat/blob/master/scripts/cheat.bash>
 - <https://github.com/cheat/cheat/blob/master/scripts/cheat.fish>
+- <https://github.com/cheat/cheat/blob/master/scripts/cheat.zsh>
 
-The **bash**/**zsh** scripts provide optional integration with **fzf**, if the
-latter is available on your **PATH**.
+The **bash** and **zsh** scripts provide optional integration with **fzf**, if
+the latter is available on your **PATH**.
 
 The installation process will vary per system and shell configuration, and thus
 will not be discussed here.
@@ -158,6 +159,10 @@ ENVIRONMENT
 : The path at which the config file is available. If **CHEAT_CONFIG_PATH** is
 set, all other config paths will be ignored.
 
+**CHEAT_USE_FZF**
+
+: If set, autocompletion scripts will attempt to integrate with **fzf**.
+
 
 BUGS
 ====