w3m: add page (#949)

pages/common/w3m.md

@@ -0,0 +1,11 @@
+# w3m
+
+> A text-based web browser.
+
+- Open an URL:
+
+`w3m {{http://example.com}}`
+
+- Quit w3m:
+
+`'q' then 'y'`