Fix lint-md so it works in local repo and when used in npm package

Author: Jeremy Wiebe

docs/bin/lint-md

@@ -2,18 +2,23 @@
 
 # Lints Markdown files using Mobify's `.remarkrc` configuration.
 BIN="${BASH_SOURCE[0]}"
-BIN_DIR="$(cd "$(dirname "$BIN")" && pwd)"
 
 # We jump through some hoops here because we symlink the node module's
 # bin into the docs/bin/ directory and we want to support invoking
 # via the symlink and directly via `/docs/bin/lint-md`
-if [ -h "$BIN" ]; then
+while [ -h "$BIN" ]; do
     # Dereference the symlink
-    BIN="$BIN_DIR/$(readlink "$BIN")"
-fi
-BIN_DIR="$(cd "$(dirname "$BIN")" && pwd)"
+    BIN="$(cd "$(dirname "$BIN")" && pwd)/$(readlink "$BIN")"
+done
 
-REMARK_RC="$BIN_DIR/../remarkrc"
-REMARK_CLI="$(npm bin)/remark"
+DOCS_DIR="$(cd "$(dirname "$BIN")/.." && pwd)"
+REMARK_RC="$DOCS_DIR/remarkrc"
+
+# This is tricky. `remark` is a dep of mobify-code-style
+# and so won't show up in `node_modules/.bin` of a project
+# that uses mobify-code-style. We have to move into the
+# the mobify-code-style /docs directory and find the npm
+# bin directory relative that _that_ to find remark!
+REMARK_CLI="$(cd "$DOCS_DIR" && npm bin)/remark"
 
 $REMARK_CLI --rc-path $REMARK_RC "$@"