Fix Trailing White Space, Add NEWS item for #7099

Author: skitsy24

..Rcheck/00check.log

@@ -0,0 +1,10 @@
+* using log directory ‘/home/skit/data.table/..Rcheck’
+* using R version 3.5.0 (2018-04-23)
+* using platform: x86_64-pc-linux-gnu (64-bit)
+* using session charset: UTF-8
+* using option ‘--no-manual’
+* checking for file ‘./DESCRIPTION’ ... ERROR
+Required fields missing or empty:
+  ‘Author’ ‘Maintainer’
+* DONE
+Status: 1 ERROR

NEWS.md

@@ -50,6 +50,8 @@
 
 8. `test()` now reports multiple expected warnings more clearly when `warning=` has length greater than 1L, instead of printing a collapsed or repeated mismatch summary after messages like `Test 1 produced 1 warnings but expected 2`, [#7092](https://github.com/Rdatatable/data.table/issues/7092). Expected and observed warnings are now printed on separate aligned lines, making small differences easier to spot. Thanks @MichaelChirico for the report, @ben-schwen for assistance, and @lucaslarson25, @tjdavis51, @D3VTHSTVR, and @car723 for the fix.
 
+11. `fread()` now correctly preserves empty trailing fields when `fill=TRUE` is used with irregular rows, [#7099](https://github.com/Rdatatable/data.table/issues/7099). Thanks to @aitap for the report and @skitsy24 for the fix.
+
 ### Notes
 
 1. {data.table} now depends on R 3.5.0 (2018).

R/print.data.table.R

@@ -22,7 +22,7 @@ print.data.table = function(x, topn=getOption("datatable.print.topn"),
   stopifnot(isTRUEorFALSE(class))
   if (col.names == "none" && class)
     warningf("Column classes will be suppressed when col.names is 'none'")
-  
+
   if (!shouldPrint(x)) {
     #  := in [.data.table sets .global$print=address(x) to suppress the next print i.e., like <- does. See FAQ 2.22 and README item in v1.9.5
     # The issue is distinguishing "> DT" (after a previous := in a function) from "> DT[,foo:=1]". To print.data.table(), there
@@ -41,8 +41,8 @@ print.data.table = function(x, topn=getOption("datatable.print.topn"),
     is_print_call = FALSE
     if (identical(SYS[[1L]][[1L]], print)) {
       is_print_call = TRUE
-    } 
-      # nocov start 
+    }
+      # nocov start
       else if (typeof(SYS[[1L]][[1L]]) == "promise") {
        # in R 3.4 and R 3.5, auto-print uses a promise to reference base::print due to lazy loading
        # safely evaluate promise to get the actual function