gitlab-ci: rename lint builds to start in lint:

.gitlab-ci.yml

@@ -99,21 +99,21 @@ upload:help:stage:
 
 # Lint builds
 
-build:debian10-iwyu:
+lint:debian10-iwyu:
     extends:
         - .debian10_iwyu
         - .cmake_build_linux
         - .linux_builder_tags
         - .run_automatically
 
-build:fedora34-tidy:
+lint:fedora34-tidy:
     extends:
         - .fedora34_tidy
         - .cmake_build_linux
         - .linux_builder_tags_qt
         - .run_automatically
 
-build:fedora34-sphinx:
+lint:fedora34-sphinx:
     extends:
         - .fedora34_sphinx
         - .cmake_build_linux