hledger-*: add pages for seven hledger subcommands (#12828)

Co-authored-by: K.B.Dharun Krishna <kbdharunkrishna@gmail.com>
Co-authored-by: Juri Dispan <juri.dispan@posteo.net>
Co-authored-by: spageektti <git@spageektti.cc>

pages/common/hledger-add.md

@@ -0,0 +1,24 @@
+# hledger add
+
+> Record new transactions with interactive prompting in the console.
+> More information: <https://hledger.org/hledger.html#add>.
+
+- Record new transactions, saving to the default journal file:
+
+`hledger add`
+
+- Add transactions to `2024.journal`, but also load `2023.journal` for completions:
+
+`hledger add --file {{path/to/2024.journal}} --file {{path/to/2023.journal}}`
+
+- Provide answers for the first four prompts:
+
+`hledger add {{today}} '{{best buy}}' {{expenses:supplies}} '{{$20}}'`
+
+- Show `add`'s options and documentation with `$PAGER`:
+
+`hledger add --help`
+
+- Show `add`'s documentation with `info` or `man` if available:
+
+`hledger help add`