Generate Shell completions

[SergioGasquez]

Uses clap_complete to generate shell completions. Usage example:

espflash completions bash > /usr/share/bash-completion/completions/espflash.bash

Note for cargo-espflash the completions have to be appended to the cargo completions

Test

These are the test that I did in my environment (using Linux and fish shell).

espflash

1. Install the crate from my branch:

   cargo install espflash --git https://github.com/SergioGasquez/espflash --branch feature/shell-completions

2. Generate completions:

   espflash completions fish > espflash.fish

3. Move the generated completions:

   sudo mv espflash.fish /usr/share/fish/completions/espflash.fish

4. Here is the result of writing espflash and tabbing:

   ❯ espflash
   board-info                    (Establish a connection with a target device)
   completions                      (Generate completions for the given shell)
   flash                             (Flash an application to a target device)
   help            (Print this message or the help of the given subcommand(s))
   monitor                          (Open the serial monitor without flashing)
   partition-table                          (Operations for partitions tables)
   save-image           (Save the image to disk instead of flashing to device)
   write-bin  (Writes a binary file to a specific address in the chip's flash)

cargo-espflash

1. Install the crate from my branch:

   cargo install cargo-espflash --git https://github.com/SergioGasquez/espflash --branch feature/shell-completions

2. Generate completions:

   cargo espflash completions fish > cargo-espflash.fish

3. Append the generated completions to cargo's completions:

   sudo cat cargo-espflash.fish >> /usr/share/fish/completions/cargo.fish

4. Here is the result of writting cargo espflash and tabbing:

   ❯ cargo espflash completions fish > cargo-espflash.fish
   board-info           (Establish a connection with a target device)
   completions             (Generate completions for the given shell)
   flash          (Build and flash an application to a target device)
   help   (Print this message or the help of the given subcommand(s))
   monitor                 (Open the serial monitor without flashing)
   partition-table                 (Operations for partitions tables)
   save-image  (Save the image to disk instead of flashing to device)

[jessebraham]

LGTM, thanks!