slapt-src, spi: add page, slapt-get: fix example (#5014)

pages/linux/slapt-src.md

@@ -0,0 +1,25 @@
+# slapt-src
+
+> A utility to automate building of slackbuilds.
+> SlackBuild sources need to be configured in the slapt-srcrc file.
+> More information: <https://github.com/jaos/slapt-src>.
+
+- Update the list of available slackbuilds and versions:
+
+`slapt-src --update`
+
+- List all available slackbuilds:
+
+`slapt-src --list`
+
+- Fetch, build and install the specified slackbuild(s):
+
+`slapt-src --install {{slackbuild_name}}`
+
+- Locate slackbuilds of interest by their name or description:
+
+`slapt-src --search {{search_term}}`
+
+- Display information about a slackbuild:
+
+`slapt-src --show {{slackbuild_name}}`