Rename "syntax" package to "lexers"

lexers/stxDockerfile.go

@@ -0,0 +1,30 @@
+//go:build stxDockerfile || stxAll
+
+package lexers
+
+func init() {
+	syntaxMap["dockerfile"] = &lazySyntax{init: func() []byte {
+		return []byte(`filetype: dockerfile
+rules:
+    - keyword: "(?i)^(FROM|MAINTAINER|RUN|CMD|LABEL|EXPOSE|ENV|ADD|COPY|ENTRYPOINT|VOLUME|USER|WORKDIR|ONBUILD|ARG|HEALTHCHECK|STOPSIGNAL|SHELL)[[:space:]]"
+    - statement: "(\\(|\\)|\\[|\\])"
+    - special: "&&"
+    - comment:
+        start: "#"
+        end: "$"
+        rules:
+            - todo: "(TODO|XXX|FIXME):?"
+    - constant.string:
+        start: "\""
+        end: "\""
+        skip: "\\\\."
+        rules:
+            - constant.specialChar: "\\\\."
+    - constant.string:
+        start: "'"
+        end: "'"
+        skip: "\\\\."
+        rules:
+            - constant.specialChar: "\\\\."`)
+	}}
+}