patch 8.1.0362: cannot get the script line number when executing a function

Problem:    Cannot get the script line number when executing a function.
Solution:   Store the line number besides the script ID. (Ozaki Kiichi,
            closes #3362)  Also display the line number with ":verbose set".
diff --git a/runtime/doc/eval.txt b/runtime/doc/eval.txt
index 21cb4ab..2ff124b 100644
--- a/runtime/doc/eval.txt
+++ b/runtime/doc/eval.txt
@@ -3798,7 +3798,10 @@
 			<abuf>		autocmd buffer number (as a String!)
 			<amatch>	autocmd matched name
 			<sfile>		sourced script file or function name
-			<slnum>		sourced script file line number
+			<slnum>		sourced script line number or function
+					line number
+			<sflnum>	script file line number, also when in
+					a function
 			<cword>		word under the cursor
 			<cWORD>		WORD under the cursor
 			<client>	the {clientid} of the last received
@@ -5931,6 +5934,7 @@
 				     (|mapmode-ic|)
 		  "sid"	     The script local ID, used for <sid> mappings
 			     (|<SID>|).
+		  "lnum"     The line number in "sid", zero if unknown.
 		  "nowait"   Do not wait for other, longer mappings.
 			     (|:map-<nowait>|).