Add troubleshooting advice for terminfos not installed remotely (#55)

ssh passes the client's value of $TERM to the server by default, and the srcf terminals don't support all terminal types. (e.g. xterm-kitty from the kitty term emulator - and kitty gets picked as the default term emulator by some distros/compositors)

content/reference/shell-and-files/ssh.md

@@ -79,3 +79,34 @@ please use **doom**, which has fingerprints:
     ED25519  SHA256:kh1Sr6Nrlp/vK9ijKZ43/IQ2tqdPzY/fnZdnGBIKgIM
     RSA      MD5:f1:ee:8c:a7:7a:cb:f7:c7:dc:c5:7e:56:9a:83:f5:bc
     RSA      SHA256:c1dlaFnPyJ44CnjZIeV6zLHQCPlIH9Og0K3dL16XGfo
+
+
+## Troubleshooting
+
+### Unsupported term-type environment variable
+If the terminal behaves incorrectly on certain keypresses - such as by
+outputting weird glyphs, or by not removing characters when inputting a
+backspace - then it is possible ssh has misconfigured the `TERM`
+environment variable.
+
+This can be checked by running `toe -a | grep $TERM`. (`toe -a` lists
+all supported values for the `TERM` variable, and `| grep $TERM`
+performs a search within `toe`'s output to try to find your session's
+value of `$TERM`). If running the command shows no output, then your
+value of `TERM` is unsupported.
+
+You can temporarily select a more general terminal type
+(`xterm-256color` should work) for your session by setting the `TERM`
+environment variable when running `ssh`:
+```bash
+TERM=xterm-256color ssh ...
+```
+To correct this persistently, run the following command (on your
+device):
+```bash
+infocmp -a $TERM | ssh <Your CRSid>@shell.srcf.net tic -x -
+```
+This will install your device's terminal-type to your account's home
+directory (inside `~/.terminfo/`). You will not need to make any manual
+changes to contents of this directory. Your terminal should now work
+correctly for all subsequent sessions.

content/tutorials/shell-and-files/logging-in.md

@@ -78,6 +78,13 @@ complex and multi-layered file system on our shell server, which happens
 to be your home directory. `pwd` tells you where you are in this
 organized mess!
 
+{{< alert type="info" >}}
+If the terminal behaves incorrectly on certain keypresses - such as by
+outputting weird glyphs, or by not removing characters when inputting a
+backspace - [then it is possible ssh has misconfigured the `TERM`
+environment variable.]({{< relref "/reference/shell-and-files/ssh#unsupported-term-type-environment-variable" >}})
+{{<  /alert >}}
+
 The last command we'll try is `cd public_html`. This **changes your
 directory** to `public_html`. You're now on a different street!