add docs of linting scripts

Author: stevemao

diff-so-fancy

@@ -48,7 +48,7 @@ colorize_context_line () {
 }
 
 mark_empty_lines () {
-	$SED -E "s/^$color_code_regex[\+\-]$reset_color\s*$/$invert_color\1 $reset_escape/g"
+  $SED -E "s/^$color_code_regex[\+\-]$reset_color\s*$/$invert_color\1 $reset_escape/g"
 }
 
 strip_leading_symbols () {

readme.md

@@ -114,6 +114,13 @@ brew install entr
 ls --color=never diff-so-fancy test/*.bats | entr bats test
 ```
 
+Be sure to lint your scripts via shellcheck
+
+```sh
+brew install shellcheck
+shellcheck diff-so-fancy update-deps.sh
+```
+
 ## License
 
 MIT