Move pages under tldr, lint run.sh, update docs

tldr/gnucash

@@ -0,0 +1,21 @@
+---
+syntax: markdown
+tags: [tldr, common]
+source: https://github.com/tldr-pages/tldr.git
+---
+# gnucash
+
+> Personal and small-business financial-accounting software.
+> More information: <https://gnucash.org>.
+
+- Launch GnuCash and load the previously opened file:
+
+`gnucash`
+
+- Launch GnuCash and load the specified file:
+
+`gnucash {{path/to/file.gnucash}}`
+
+- Launch GnuCash and load an empty file:
+
+`gnucash --nofile`