clangd, valac, x8: replace broken links (#18428)

Co-authored-by: Managor <42655600+Managor@users.noreply.github.com>
Co-authored-by: Dylan <145150333+dmmqz@users.noreply.github.com>

pages/common/clangd.md

@@ -2,7 +2,7 @@
 
 > Language server that provides IDE-like features to editors.
 > It should be used via an editor plugin rather than invoked directly.
-> More information: <https://manpages.ubuntu.com/manpages/focal/man1/clangd.1.html>.
+> More information: <https://manpages.ubuntu.com/manpages/man1/clangd.1.html>.
 
 - Display available options:
 

pages/common/valac.md

@@ -2,7 +2,7 @@
 
 > Vala code compiler.
 > Tutorial: <https://wiki.gnome.org/Projects/Vala/Tutorial>.
-> More information: <https://docs.vala.dev/tutorials/programming-language/main/07-00-tools/07-01-valac.html/>.
+> More information: <https://docs.vala.dev/tutorials/programming-language/main/07-00-tools/07-01-valac.html>.
 
 - Compile a vala file, with gtk+:
 

pages/common/x8.md

@@ -1,7 +1,7 @@
 # x8
 
 > A hidden parameters discovery suite for identifying vulnerable or interesting web parameters.
-> More information: <https://sh1yo.art/x8docs/>.
+> More information: <https://github.com/Sh1Yo/x8/blob/main/docs.md>.
 
 - Check hidden parameters in a URL query: