Add Yosys linter for Verilog files. (#3713)

* Add yosys for verilog files.

* Add handler test for yosys.

* fix typo in yosys handler test

* fix array order in yosys handler test

* add yosys linter to filetype defaults test

* fix duplicate tag

* add 'yosys' to 'ale-supported-languages-and-tools.txt'

doc/ale-supported-languages-and-tools.txt

@@ -550,6 +550,7 @@ Notes:
   * `verilator`
   * `vlog`
   * `xvlog`
+  * `yosys`
 * VHDL
   * `ghdl`
   * `vcom`

doc/ale-verilog.txt

@@ -3,7 +3,7 @@ ALE Verilog/SystemVerilog Integration                     *ale-verilog-options*
 
 
 ===============================================================================
-ALE can use five different linters for Verilog HDL:
+ALE can use six different linters for Verilog HDL:
 
   HDL Checker
     Using `hdl_checker --lsp`
@@ -20,6 +20,9 @@ ALE can use five different linters for Verilog HDL:
   Vivado
     Using `xvlog`
 
+  Yosys
+    Using `ysoys -Q -T -p 'read_verilog'`
+
 By default, both 'verilog' and 'systemverilog' filetypes are checked.
 
 You can limit 'systemverilog' files to be checked using only 'verilator' by
@@ -114,5 +117,26 @@ g:ale_verilog_xvlog_options                       *g:ale_verilog_xvlog_options*
   This variable can be changed to modify the flags/options passed to 'xvlog'.
 
 
+===============================================================================
+yosys                                                       *ale-verilog-yosys*
+
+g:ale_verilog_yosys_executable                 *g:ale_verilog_yosys_executable*
+                                               *b:ale_verilog_yosys_executable*
+  Type: |String|
+  Default: `'yosys'`
+
+  This variable can be changed to the path to the 'yosys' executable.
+
+
+g:ale_verilog_yosys_options                       *g:ale_verilog_yosys_options*
+                                                  *b:ale_verilog_yosys_options*
+  Type: |String|
+  Default: `'-Q -T -p ''read_verilog %s'''`
+
+  This variable can be changed to modify the flags/options passed to 'yosys'.
+  By default, Yosys is an interative program. To obtain linting functionality,
+  the `'read_verilog'` command is used.
+
+
 ===============================================================================
   vim:tw=78:ts=2:sts=2:sw=2:ft=help:norl:

doc/ale.txt

@@ -3067,6 +3067,7 @@ documented in additional help files.
     verilator.............................|ale-verilog-verilator|
     vlog..................................|ale-verilog-vlog|
     xvlog.................................|ale-verilog-xvlog|
+    yosys.................................|ale-verilog-yosys|
   vhdl....................................|ale-vhdl-options|
     ghdl..................................|ale-vhdl-ghdl|
     hdl-checker...........................|ale-vhdl-hdl-checker|