Fix documentation

Author: silvanocerza

docs/UPGRADING.md

@@ -8,8 +8,8 @@ Here you can find a list of migration guides to handle breaking changes between
 
 Both the `board attach` CLI command and the `cc.arduino.cli.commands.v1.BoardAttach` gRPC command have been removed.
 
-They are not replaced by any new command, the only way to get the same behaviour is to edit the `sketch.json` file either manually or automatically with other tools.
-
+They are not replaced by any new command, the only way to get the same behaviour is to edit the `sketch.json` file
+either manually or automatically with other tools.
 
 ## 0.28.0
 

docs/sketch-specification.md

@@ -71,11 +71,10 @@ the `data` folder, so any non-code files outside the `data` folder are stripped.
 Arduino CLI and Arduino Web Editor use a file named sketch.json, located in the sketch root folder, to store sketch
 metadata.
 
-The `cpu` key contains the board configuration information. This can be set via
-[`arduino-cli board attach`](commands/arduino-cli_board_attach.md) or by selecting a board in the Arduino Web Editor
-while the sketch is open. With this configuration set, it is not necessary to specify the `--fqbn` or `--port` flags to
-the [`arduino-cli compile`](commands/arduino-cli_compile.md) or [`arduino-cli upload`](commands/arduino-cli_upload.md)
-commands when compiling or uploading the sketch.
+The `cpu` key contains the board configuration information. This can be set manually or by selecting a board in the
+Arduino Web Editor while the sketch is open. With this configuration set, it is not necessary to specify the `--fqbn` or
+`--port` flags to the [`arduino-cli compile`](commands/arduino-cli_compile.md) or
+[`arduino-cli upload`](commands/arduino-cli_upload.md) commands when compiling or uploading the sketch.
 
 The `included_libs` key defines the library versions the Arduino Web Editor uses when the sketch is compiled. This is
 Arduino Web Editor specific because all versions of all the Library Manager libraries are pre-installed in Arduino Web

mkdocs.yml

@@ -52,7 +52,6 @@ nav:
   - Command reference:
       - arduino-cli: commands/arduino-cli.md
       - board: commands/arduino-cli_board.md
-      - board attach: commands/arduino-cli_board_attach.md
       - board details: commands/arduino-cli_board_details.md
       - board list: commands/arduino-cli_board_list.md
       - board listall: commands/arduino-cli_board_listall.md