Updated SC2155 (markdown)

SC2155.md

@@ -1,6 +1,6 @@
 ## Declare and assign separately to avoid masking return values.
 
-### Problematic code:
+### Problematic code in the case of `export`:
 
 ```sh
 export foo="$(mycmd)"
@@ -29,3 +29,16 @@ export foo
 ```
 
 Shellcheck does not warn about `export foo=bar` because `bar` is a literal and not a command substitution with an independent return value. It also does not warn about `local -r foo=$(cmd)`, where declaration and assignment must be in the same command.
+
+### Problematic code in the case of `local`:
+
+```sh
+local foo="$(mycmd)"
+```
+
+### Correct code:
+
+```sh
+local foo
+foo=$(mycmd)
+```