syntaxes: condense and/or correct some extension regexes

syntax/c.nanorc

@@ -1,6 +1,6 @@
 ## Here is an example for C/C++.
 
-syntax c "\.(c(c|pp|xx|\+\+)?|C)$" "\.(h(h|pp|xx)?|H)$" "\.ii?$"
+syntax c "\.([ch](pp|xx)?|C|cc|c\+\+|H|hh|ii?)$"
 magic "^(C|C\+\+) (source|program)"
 comment "//"
 

syntax/changelog.nanorc

@@ -1,6 +1,6 @@
 ## Colouring for Changelogs.
 
-syntax changelog "Change[Ll]og.*"
+syntax changelog "Change[Ll]og[^/]*$"
 
 # Author lines.
 color green "^(19|20).*$"

syntax/debian.nanorc

@@ -1,6 +1,6 @@
 ## Here is an example for apt's sources.list.
 
-syntax sources.list "sources\.list(~|\.old|\.save)?$" "sources\.list\.d/.*\.list(~|\.old|\.save)?$"
+syntax sources.list "sources\.list(\.d/.*\.list)?(~|\.old|\.save)?$"
 comment "#"
 
 # Coloring the deb lines, working from tail to head.  First the

syntax/groff.nanorc

@@ -1,6 +1,6 @@
 ## Here is an example for groff.
 
-syntax groff "\.m[ems]$" "\.rof" "\.tmac$" "^tmac."
+syntax groff "(/tmac\.[^/]+$|\.(m[ems]|rof|tmac)$)"
 comment ".\""
 
 # The argument of .ds or .nr

syntax/makefile.nanorc

@@ -1,6 +1,6 @@
 ## Here is an example for Makefiles.
 
-syntax makefile "Makefile[^/]*$" "\.(make|mk)$"
+syntax makefile "(Makefile[^/]*$|\.(make|mk)$)"
 magic "makefile script"
 comment "#"
 

syntax/rust.nanorc

@@ -4,7 +4,7 @@
 
 ## NOTE: Rules are applied in order: later rules re-colorize matching text.
 
-syntax rust "\.rs"
+syntax rust "\.(rlib|rs)$"
 comment "//"
 
 # Function definitions

syntax/spec.nanorc

@@ -1,6 +1,6 @@
 ## Syntax highlighting for RPM spec files.
 
-syntax spec "\.(spec$|spec\.*)"
+syntax spec "\.spec(\.[^/]+)?$"
 comment "#"
 
 # Main tags.