rustup-{set,self,completions,doc,override,component}: add page (#10729)

* rustup set: add page

* rustup self: add page

* rustup completions: add page

* rustup doc: add page

* rustup override: add page

* rustup component: add page

---------

Co-authored-by: K.B.Dharun Krishna <kbdharunkrishna@gmail.com>

pages/common/rustup-self.md

@@ -0,0 +1,12 @@
+# rustup self
+
+> Modify the `rustup` installation.
+> More information: <https://rust-lang.github.io/rustup>.
+
+- Update `rustup`:
+
+`rustup self update`
+
+- Uninstall `rustup`:
+
+`rustup self uninstall`