quote source-file so it doesn't break when it has spaces in. tidy issues.

ISSUES/0002.txt

@@ -1,3 +0,0 @@
-A plain text file issue
-
-with a short description

ISSUES/0003

@@ -1,3 +0,0 @@
-Another plain text file issue with no extension
-
-and a short description

main.scm

@@ -190,7 +190,7 @@
   (not (equal?
         "-\t-\t"
         (call-with-input-pipe
-         (string-append "git diff 4b825dc642cb6eb9a060e54bf8d69288fbee4904 --numstat HEAD -- " source-file)
+         (string-append "git diff 4b825dc642cb6eb9a060e54bf8d69288fbee4904 --numstat HEAD -- " (qs source-file))
          (cute read-line <> 4)))))
 
 (define (git-repository->paths-list)
@@ -198,7 +198,9 @@
 
 (define (git-file->string source-file)
   (->
-   (format "git show HEAD:~a" source-file)
+   source-file
+   (qs)
+   ((flip format) "git show HEAD:~a")
    (call-with-input-pipe read-lines)
    (string-intersperse "\n")))
 
@@ -281,9 +283,11 @@
            (string-prefix? "ISSUES/" source-file)
            `(li (a (@ (href ,source-file))
                    ,(->
-                     source-file
-                     ((flip format) "git show HEAD:~a")
+                     (string-append "HEAD:" source-file)
+                     (qs)
+                     ((flip format) "git show ~a")
                      (call-with-input-pipe read-line)
+                     ((lambda (x) (if (eof-object? x) (pathname-strip-directory source-file) x)))
                      (string-trim (string->char-set "# ")))))))
         source-files-list)))))
 
@@ -394,8 +398,8 @@
        (case (string->symbol (or (pathname-extension source-file) ""))
          ((jpg jpeg png gif webp webm svg apng avif svgz ico)
           (system (format "git show HEAD:~a > ~a"
-                          source-file
-                          (make-pathname html-path source-file))))))
+                          (qs source-file)
+                          (make-pathname html-path (qs source-file)))))))
      source-files-list)
     ;; if README.md, README, or README.txt exists, regenerate it as index.html.
     ;; otherwise regenerate files.html as index.html.