fix rstudio#161, remove margins when there's no details

DESCRIPTION

@@ -1,7 +1,7 @@
 Package: pagedown
 Type: Package
 Title: Paginate the HTML Output of R Markdown with CSS for Print
-Version: 0.7.1
+Version: 0.7.2
 Authors@R: c(
   person("Yihui", "Xie", role = c("aut", "cre"), email = "xie@yihui.name", comment = c(ORCID = "0000-0003-0645-5666")),
   person("Romain", "Lesur", role = c("aut", "cph"), comment = c(ORCID = "0000-0002-0721-5595")),

NEWS.md

@@ -4,6 +4,8 @@
 
 - In `chrome_print()`, fixed some connection problems to headless Chrome: in some situations, the R session tries to connect to headless Chrome before a target is created. Now, `chrome_print()` controls the target creation by connecting to the `Browser` endpoint (thanks, @gershomtripp, #158).  
 
+- In `html_resume()` template, vertical space is removed when details are omitted (thanks, @mrajeev08, #161).
+
 # CHANGES IN pagedown VERSION 0.7
 
 ## NEW FEATURES

inst/resources/css/resume.css

@@ -280,6 +280,10 @@ h1, h2{
   margin: 0.18in 0 0.1in 0;
 }
 
+.main-block:not(.concise) .details div:empty {
+  margin: 0;
+}
+
 .main-block:not(.concise) .blocks:last-child .details div{
   margin-bottom: 0;
 }