nimsuggest: more precise cursor tracking

nimsuggest/tests/tdef1.nim

@@ -0,0 +1,16 @@
+discard """
+$nimsuggest --tester $file
+>def $1
+def;;skProc;;tdef1.hello;;proc (): string{.noSideEffect, gcsafe, locks: 0.};;$file;;9;;5;;"Return hello";;100
+>def $1
+def;;skProc;;tdef1.hello;;proc (): string{.noSideEffect, gcsafe, locks: 0.};;$file;;9;;5;;"Return hello";;100
+"""
+
+proc hello(): string =
+  ## Return hello
+  "Hello"
+
+hel#[!]#lo()
+
+# v uncompleted id for sug (13,2)
+he