Document change in reference manual.
@@ -1575,6 +1575,8 @@ the following methods:
- `get_define(definename)` returns the given preprocessor symbol's
value as a string or empty string if it is not defined.
+ The method will concatenate string literals as the compiler would.
+ E.g. `"a" "b"` will become `"ab"`.
- `get_id()` returns a string identifying the compiler. For example,
`gcc`, `msvc`, [and more](Reference-tables.html#compiler-ids).
