Add docs for shell completion files.

Add small howtos for installing shell completion files to the README and
the man page.

They are still incomplete. We're missing Zsh and PowerShell.

Fixes #262

README.md

@@ -302,6 +302,16 @@ extensions.
 The syntax supported is
 [documented as part of Rust's regex library](https://doc.rust-lang.org/regex/regex/index.html#syntax).
 
+### Shell completions
+
+Shell completion files are included in the release tarball for Bash, Fish, Zsh
+and PowerShell.
+
+For **bash**, move `rg.bash-completion` to `$XDG_CONFIG_HOME/bash_completion`
+or `/etc/bash_completion.d/`.
+
+For **fish**, move `rg.fish` to `$HOME/.config/fish/completions`.
+
 ### Building
 
 `ripgrep` is written in Rust, so you'll need to grab a

doc/rg.1

@@ -409,3 +409,14 @@ ripgrep.
 Note that this must be passed to every invocation of rg.
 .RS
 .RE
+.SH SHELL COMPLETION
+.PP
+Shell completion files are included in the release tarball for Bash,
+Fish, Zsh and PowerShell.
+.PP
+For \f[B]bash\f[], move \f[C]rg.bash\-completion\f[] to
+\f[C]$XDG_CONFIG_HOME/bash_completion\f[] or
+\f[C]/etc/bash_completion.d/\f[].
+.PP
+For \f[B]fish\f[], move \f[C]rg.fish\f[] to
+\f[C]$HOME/.config/fish/completions\f[].

doc/rg.1.md

@@ -273,3 +273,13 @@ Project home page: https://github.com/BurntSushi/ripgrep
 : Clear the file type globs previously defined for TYPE. This only clears
   the default type definitions that are found inside of ripgrep. Note
   that this must be passed to every invocation of rg.
+
+# SHELL COMPLETION
+
+Shell completion files are included in the release tarball for Bash, Fish, Zsh
+and PowerShell.
+
+For **bash**, move `rg.bash-completion` to `$XDG_CONFIG_HOME/bash_completion`
+or `/etc/bash_completion.d/`.
+
+For **fish**, move `rg.fish` to `$HOME/.config/fish/completions`.