Support `1_000.toString()`; fixes #5427 (#5429)

Support calling methods on numbers with separators.

docs/v2/annotated-source/nodes.html

@@ -10237,7 +10237,7 @@ LEVEL_ACCESS = <span class="hljs-number">6</span>  <span class="hljs-comment">#
             
             <div class="content"><div class='highlight'><pre>TAB = <span class="hljs-string">&#x27;  &#x27;</span>
 
-SIMPLENUM = <span class="hljs-regexp">/^[+-]?\d+$/</span>
+SIMPLENUM = <span class="hljs-regexp">/^[+-]?(?:\d(?:_?\d)*)+$/</span>
 SIMPLE_STRING_OMIT = <span class="hljs-regexp">/\s*\n\s*/g</span>
 LEADING_BLANK_LINE  = <span class="hljs-regexp">/^[^\n\S]*\n/</span>
 TRAILING_BLANK_LINE = <span class="hljs-regexp">/\n[^\n\S]*$/</span>

docs/v2/test.html

@@ -29307,6 +29307,7 @@ test "Parser recognises binary numbers", ->
 test "call methods directly on numbers", ->
   eq 4, 4.valueOf()
   eq '11', 4.toString 3
+  eq '1000', 1_000.toString()
 
 eq -1, 3 -4
 

lib/coffeescript/nodes.js

@@ -8758,7 +8758,7 @@
   // Tabs are two spaces for pretty printing.
   TAB = '  ';
 
-  SIMPLENUM = /^[+-]?\d+$/;
+  SIMPLENUM = /^[+-]?(?:\d(?:_?\d)*)+$/;
 
   SIMPLE_STRING_OMIT = /\s*\n\s*/g;
 

src/nodes.coffee

@@ -5772,7 +5772,7 @@ LEVEL_ACCESS = 6  # ...[0]
 # Tabs are two spaces for pretty printing.
 TAB = '  '
 
-SIMPLENUM = /^[+-]?\d+$/
+SIMPLENUM = /^[+-]?(?:\d(?:_?\d)*)+$/
 SIMPLE_STRING_OMIT = /\s*\n\s*/g
 LEADING_BLANK_LINE  = /^[^\n\S]*\n/
 TRAILING_BLANK_LINE = /\n[^\n\S]*$/

test/numbers.coffee

@@ -21,6 +21,7 @@ test "Parser recognises binary numbers", ->
 test "call methods directly on numbers", ->
   eq 4, 4.valueOf()
   eq '11', 4.toString 3
+  eq '1000', 1_000.toString()
 
 eq -1, 3 -4