pages.*: fix page title (#11811)

pages/common/cs.md

@@ -1,4 +1,4 @@
-# coursier
+# cs
 
 > Application and artifact manager for the Scala language, it can install Scala applications and setup your Scala development environment.
 > Some subcommands such as `install`, `launch`, `java`, `fetch`, `resolve`, `complete-dep`, etc. have their own usage documentation.

pages/common/kubectl-replace.md

@@ -1,4 +1,4 @@
-# kubctl replace
+# kubectl replace
 
 > Replace a resource by file or `stdin`.
 > More information: <https://kubernetes.io/docs/reference/generated/kubectl/kubectl-commands#replace>.

pages/common/nix-classic.md

@@ -1,4 +1,4 @@
-# Nix classic interface
+# nix classic
 
 > A classic, stable interface to a powerful package manager that makes package management reliable, reproducible, and declarative.
 > Some Nix commands such as `nix-build`, `nix-shell`, `nix-env`, and `nix-store` have their own pages. See also: `tldr nix`.