fix #2844 #3911; add --spellsuggest to suggest symbols in scope with similar spellings on undefined symbol error (#16067)

* add --spellsuggest to suggest symbols in scope with similar spellings on undefined symbol errors
* implement --spellsuggest with 0 arguments

tests/misc/mspellsuggest.nim

@@ -0,0 +1,7 @@
+proc fooBar4*(a: int) = discard
+var fooBar9* = 0
+
+var fooCar* = 0
+type FooBar* = int
+type FooCar* = int
+type GooBa* = int

tests/misc/tspellsuggest.nim

@@ -0,0 +1,45 @@
+discard """
+  # pending bug #16521 (bug 12) use `matrix`
+  cmd: "nim c --spellsuggest:15 --hints:off $file"
+  action: "reject"
+  nimout: '''
+tspellsuggest.nim(45, 13) Error: undeclared identifier: 'fooBar'
+candidate misspellings (edit distance, lexical scope distance):
+ (1, 0): 'fooBar8' [var declared in tspellsuggest.nim(43, 9)]
+ (1, 1): 'fooBar7' [var declared in tspellsuggest.nim(41, 7)]
+ (1, 3): 'fooBar1' [var declared in tspellsuggest.nim(33, 5)]
+ (1, 3): 'fooBar2' [let declared in tspellsuggest.nim(34, 5)]
+ (1, 3): 'fooBar3' [const declared in tspellsuggest.nim(35, 7)]
+ (1, 3): 'fooBar4' [proc declared in tspellsuggest.nim(36, 6)]
+ (1, 3): 'fooBar5' [template declared in tspellsuggest.nim(37, 10)]
+ (1, 3): 'fooBar6' [macro declared in tspellsuggest.nim(38, 7)]
+ (1, 5): 'FooBar' [type declared in mspellsuggest.nim(5, 6)]
+ (1, 5): 'fooBar4' [proc declared in mspellsuggest.nim(1, 6)]
+ (1, 5): 'fooBar9' [var declared in mspellsuggest.nim(2, 5)]
+ (1, 5): 'fooCar' [var declared in mspellsuggest.nim(4, 5)]
+ (2, 5): 'FooCar' [type declared in mspellsuggest.nim(6, 6)]
+ (2, 5): 'GooBa' [type declared in mspellsuggest.nim(7, 6)]
+ (3, 0): 'fooBarBaz' [const declared in tspellsuggest.nim(44, 11)]
+'''
+"""
+
+# tests `--spellsuggest:num`
+
+
+
+# line 30
+import ./mspellsuggest
+
+var fooBar1 = 0
+let fooBar2 = 0
+const fooBar3 = 0
+proc fooBar4() = discard
+template fooBar5() = discard
+macro fooBar6() = discard
+
+proc main =
+  var fooBar7 = 0
+  block:
+    var fooBar8 = 0
+    const fooBarBaz = 0
+    let x = fooBar

tests/misc/tspellsuggest2.nim

@@ -0,0 +1,45 @@
+discard """
+  # pending bug #16521 (bug 12) use `matrix`
+  cmd: "nim c --spellsuggest --hints:off $file"
+  action: "reject"
+  nimout: '''
+tspellsuggest2.nim(45, 13) Error: undeclared identifier: 'fooBar'
+candidate misspellings (edit distance, lexical scope distance):
+ (1, 0): 'fooBar8' [var declared in tspellsuggest2.nim(43, 9)]
+ (1, 1): 'fooBar7' [var declared in tspellsuggest2.nim(41, 7)]
+ (1, 3): 'fooBar1' [var declared in tspellsuggest2.nim(33, 5)]
+ (1, 3): 'fooBar2' [let declared in tspellsuggest2.nim(34, 5)]
+ (1, 3): 'fooBar3' [const declared in tspellsuggest2.nim(35, 7)]
+ (1, 3): 'fooBar4' [proc declared in tspellsuggest2.nim(36, 6)]
+ (1, 3): 'fooBar5' [template declared in tspellsuggest2.nim(37, 10)]
+ (1, 3): 'fooBar6' [macro declared in tspellsuggest2.nim(38, 7)]
+ (1, 5): 'FooBar' [type declared in mspellsuggest.nim(5, 6)]
+ (1, 5): 'fooBar4' [proc declared in mspellsuggest.nim(1, 6)]
+ (1, 5): 'fooBar9' [var declared in mspellsuggest.nim(2, 5)]
+ (1, 5): 'fooCar' [var declared in mspellsuggest.nim(4, 5)]
+'''
+"""
+
+# tests `--spellsuggest`
+
+
+
+
+
+
+# line 30
+import ./mspellsuggest
+
+var fooBar1 = 0
+let fooBar2 = 0
+const fooBar3 = 0
+proc fooBar4() = discard
+template fooBar5() = discard
+macro fooBar6() = discard
+
+proc main =
+  var fooBar7 = 0
+  block:
+    var fooBar8 = 0
+    const fooBarBaz = 0
+    let x = fooBar