chore(lint-style.sh): remove duplicate check for case clashes (#15027)

The check_case action (run earlier in the same workflow step) runs the same check across the entire repository.

scripts/lint-style.sh

@@ -28,7 +28,7 @@ set -exo pipefail
 #    Exceptions are maintained in `scripts/style-exceptions.txt`.
 #    (Rewriting these checks in Lean is work in progress.)
 # 2. The remainder of this shell script
-#    contains some lints on the global repository.
+#    contains a lint on the global repository.
 #
 # TODO: This is adapted from the linter for mathlib3. It should be rewritten in Lean.
 
@@ -47,8 +47,6 @@ lake exe lint_style --github
 
 # 2. Global checks on the mathlib repository
 
-# 2.1 Check for executable bit on Lean files
-
 executable_files="$(find . -name '*.lean' -type f \( -perm -u=x -o -perm -g=x -o -perm -o=x \))"
 
 if [[ -n "$executable_files" ]]
@@ -57,14 +55,3 @@ then
 	echo "$executable_files"
 	exit 1
 fi
-
-# 2.2 Check that there are no filenames with the same lower-case reduction
-
-# `uniq -D`: print all duplicate lines
-ignore_case_clashes="$(git ls-files | sort --ignore-case | uniq -D --ignore-case)"
-
-if [ -n "${ignore_case_clashes}" ]; then
-	printf $'The following files have the same lower-case form:\n\n%s\n
-Please, make sure to avoid such clashes!\n' "${ignore_case_clashes}"
-	exit 1
-fi