patch 8.2.1347: cannot easily get the script ID
Problem: Cannot easily get the script ID.
Solution: Support expand('<SID>').
diff --git a/runtime/doc/map.txt b/runtime/doc/map.txt
index 0ad43d4..79c46f7 100644
--- a/runtime/doc/map.txt
+++ b/runtime/doc/map.txt
@@ -1167,6 +1167,10 @@
the script it was defined in. This makes it possible that the command calls a
local function or uses a local mapping.
+In case the value is used in a context where <SID> cannot be correctly
+expanded, use the expand() function: >
+ let &includexpr = expand('<SID>') .. 'My_includeexpr()'
+
Otherwise, using "<SID>" outside of a script context is an error.
If you need to get the script number to use in a complicated script, you can