refactor(api): make range in nvim_parse_cmd an array

Changes the `range` value in `nvim_parse_cmd` into an array to describe
range information more concisely. Also makes `range` and `count` be
mutually exclusive by making count `-1` when command takes a range
instead of a count. Additionally corrects the behavior of `count` for
built-in commands by making the default count `0`.

test/functional/api/vim_spec.lua

@@ -3104,9 +3104,7 @@ describe('API', function()
         cmd = 'echo',
         args = { 'foo' },
         bang = false,
-        line1 = -1,
-        line2 = -1,
-        range = 0,
+        range = {},
         count = -1,
         reg = '',
         addr = 'none',
@@ -3142,9 +3140,7 @@ describe('API', function()
         cmd = 'substitute',
         args = { '/math.random/math.max/' },
         bang = false,
-        line1 = 4,
-        line2 = 6,
-        range = 2,
+        range = { 4, 6 },
         count = -1,
         reg = '',
         addr = 'line',
@@ -3180,9 +3176,7 @@ describe('API', function()
         cmd = 'buffer',
         args = {},
         bang = false,
-        line1 = 1,
-        line2 = 1,
-        range = 1,
+        range = {},
         count = 1,
         reg = '',
         addr = 'buf',
@@ -3218,9 +3212,7 @@ describe('API', function()
         cmd = 'put',
         args = {},
         bang = false,
-        line1 = 1,
-        line2 = 1,
-        range = 0,
+        range = {},
         count = -1,
         reg = '+',
         addr = 'line',
@@ -3256,9 +3248,7 @@ describe('API', function()
         cmd = 'write',
         args = {},
         bang = true,
-        line1 = 1,
-        line2 = 1,
-        range = 0,
+        range = {},
         count = -1,
         reg = '',
         addr = 'line',
@@ -3294,9 +3284,7 @@ describe('API', function()
         cmd = 'split',
         args = { 'foo.txt' },
         bang = false,
-        line1 = 1,
-        line2 = 1,
-        range = 0,
+        range = {},
         count = -1,
         reg = '',
         addr = '?',
@@ -3333,9 +3321,7 @@ describe('API', function()
         cmd = 'MyCommand',
         args = { 'test', 'it' },
         bang = true,
-        line1 = 4,
-        line2 = 6,
-        range = 2,
+        range = { 4, 6 },
         count = -1,
         reg = '',
         addr = 'line',
@@ -3371,9 +3357,7 @@ describe('API', function()
         cmd = 'argadd',
         args = { 'a.txt' },
         bang = false,
-        line1 = 0,
-        line2 = 0,
-        range = 0,
+        range = {},
         count = -1,
         reg = '',
         addr = 'arg',
@@ -3410,9 +3394,7 @@ describe('API', function()
         cmd = 'MyCommand',
         args = { 'test it' },
         bang = false,
-        line1 = -1,
-        line2 = -1,
-        range = 0,
+        range = {},
         count = -1,
         reg = '',
         addr = 'none',
@@ -3443,46 +3425,6 @@ describe('API', function()
         }
       }, meths.parse_cmd('MyCommand test it', {}))
     end)
-    it('sets correct default range', function()
-      command('command -range=% -addr=buffers MyCommand echo foo')
-      command('new')
-      eq({
-        cmd = 'MyCommand',
-        args = {},
-        bang = false,
-        line1 = 1,
-        line2 = 2,
-        range = 0,
-        count = -1,
-        reg = '',
-        addr = 'buf',
-        magic = {
-            file = false,
-            bar = false
-        },
-        nargs = '0',
-        nextcmd = '',
-        mods = {
-          browse = false,
-          confirm = false,
-          emsg_silent = false,
-          hide = false,
-          keepalt = false,
-          keepjumps = false,
-          keepmarks = false,
-          keeppatterns = false,
-          lockmarks = false,
-          noautocmd = false,
-          noswapfile = false,
-          sandbox = false,
-          silent = false,
-          vertical = false,
-          split = "",
-          tab = 0,
-          verbose = -1
-        }
-      }, meths.parse_cmd('MyCommand', {}))
-    end)
     it('errors for invalid command', function()
       eq('Error while parsing command line', pcall_err(meths.parse_cmd, 'Fubar', {}))
       command('command! Fubar echo foo')